A dramatic round of Champions League quarterfinal first legs has left three ties fascinatingly poised. Barcelona's 3-1 win at Paris Saint-Germain makes it the only overwhelming favorite to be one of the four teams involved in Friday's semifinal draw.
Here is what to look out for in what could be a cataclysmic couple of days across Europe:
Tuesday, April 21
Bayern Munich (1) vs. FC Porto (3)
Last week Jurgen Klopp took us all by surprise and announced he was leaving Borussia Dortmund. Will this week see something similar with Pep Guardiola at Bayern Munich? It has been an astonishing few days for the German giant, which was stunned by its deserved 3-1 loss at Porto last Wednesday.
Mistakes by Manuel Neuer and Dante in the opening 15 minutes allowed Ricardo Quaresma to score twice, and while Thiago Alcantara halved the deficit, Bayern's second-half performance, in which it conceded a third, was described as worse than last season's 4-0 capitulation to Real Madrid in the semifinal stage. What happened next was just as surprising: club doctor Hans-Wilhelm Muller-Wohlfahrt and his three-man medical team resigning en masse, claiming they had been blamed for the Porto defeat.
Among the players injured for the tie were Franck Ribery, Arjen Robben, David Alaba, Bastian Schweinsteiger, Javi Martinez and Medhi Benatia. Guardiola and Müller-Wohlfahrt had clashed over the treatment of Thiago last season, and a video of the coach sarcastically clapping Muller-Wohlfahrt in the dugout after Benatia was injured against Leverkusen further pointed at obvious tensions in the relationship.
Guardiola was asked about that at his press conference last Friday and said, "That was just me being disappointed, it had nothing to do with Muller-Wohlfahrt."
Although Bayern is just one win away from another Bundesliga title and is in the German Cup final, Tuesday's game could decide the future of Guardiola. Despite insisting that he will be at the club next season, the final one of his three-year contract, there has been very little word from the club's senior figures. "The club's leadership has been strangely silent on this issue," wrote German publication Bild. With president Uli Hoeness serving jail time for tax evasion, another German outlet, Die Welt wondered: "Would this have happened under Hoeness?"
There is still time for Bayern to turn this around, but Porto showed it would be no pushover in Munich. After Saturday's league win at Hoffenheim, Guardiola spoke to the players for so long in the dressing-room afterwards that they almost missed the bus home.
"He was very emotional and said he was proud of us," said goalscorer Sebastian Rode. "He believes that we can overcome problems and reminded us to stay calm."
Not only will Bayern's potential Champions League rivals be watching this tie with interest, but all big clubs thinking about upgrading their coaches this summer will be too. But has this episode seen Guardiola's halo slip a little?
Barcelona (3) vs. PSG (1)
Three weeks is a long time in soccer. It was three weeks ago when PSG beat Chelsea with 10 men at Stamford Bridge: the first time the French side had beaten a top-ranked European opponent in a Champions League knockout game. Coach Laurent Blanc was praised for his success and the French media insisted he was safe, he had to be safe, in his job for next season. After all, PSG is top of the table in France, has won the League Cup final and is in the French Cup final; on course for a domestic treble that has never been done before.
But losing at home to Barcelona has changed everything again; Blanc is under pressure again.
This is despite PSG missing Marco Verratti and Zlatan Ibrahimovic (suspended) and Thiago Motta (injured) and having captain Thiago Silva limp off after 15 minutes. David Luiz had been ruled out for a month 10 days earlier: he was clearly not fit yet played and was nutmegged for two Luis Suarez goals.
Anything that could have gone wrong for Blanc did. Seeing Suarez score two, while his compatriot Edinson Cavani continued to struggle for PSG, could not have helped. Blanc was asked to compare the two Uruguayans and spoke of Suarez's stellar supporting cast without mentioning that his two goals were purely self-created. They did each leave fans wondering if Salvatore Sirigu is the right goalkeeper to go deep in Europe; Petr Cech would be a popular catch for next season.
This game also marks the return of Ibrahimovic to Camp Nou; the Swede scored 22 goals in his only season as a Barcelona player, which was more memorable for his disparaging comments about Lionel Messi and his goody-two-shoes teammates who never stood up to then-coach Guardiola.
Ibra may have been taken aback by Messi's stronger approach with Luis Enrique this season.
His return will probably be too little too late for PSG, and with one season left on his contract, talk will probably soon start about his next destination.
Wednesday, April 22
Real Madrid (0) vs. Atlético Madrid (0)
Real Madrid coach Carlo Ancelotti called the first leg about right, describing it as "the best of the worst results [possible]." His team did not lose, unlike three of its previous four encounters against Atlético this season, and in the first half it would have scored if not for a series of sensational saves from the man of the match, goalkeeper Jan Oblak. Atletico boss Diego Simeone was also happy: to have weathered that Real storm and not conceded an away goal, leaving his team knowing that a scored draw will be enough to reach the semifinals.
Momentum can change quickly, and as soon as Real Madrid beat Malaga over the weekend, it was on the back foot. Gareth Bale limped off after four minutes and will miss the game, as will Luka Modric, whose knee ligament strain could very well end his season.
While Bale's absence is likely to see Ancelotti switch to the 4-4-2 many have called for this season, Modric's absence is a huge blow.
Karim Benzema has a knee strain and also a doubt. Marcelo is suspended, and Fabio Coentrao, whose link-up play with countryman Cristiano Ronaldo is a threat, will deputize.
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Ancelotti knows that he will be under severe pressure if Real is eliminated, but perhaps the selection will work in his favor. Simeone will plan for either Madrid's 4-4-2 (as is usually the case without Bale) or 4-3-3 with Jese replacing the Welshman, but there is a third option: a 4-3-3 with Asier Illarramendi replacing Modric, and James Rodriguez pushed further forward in a free role around the strikers. These teams know each other so well that maybe a slight tweak in the system could make the difference. It could be a tense evening at the Bernabeu.
Monaco (0) vs. Juventus (1)
Last week Darren Tulett, the charismatic English host on BeInSport's French channel, turned to his expert panel and, with a serious expression, asked: "So can Monaco go to UEFA and ask to play this second leg away from home?" His reason was obvious: only Real Madrid and Barcelona have won more league matches away from home this season, and Monaco, playing in its half-empty Stade Louis II stadium, is simply not as good playing in front of an average of 7,901 spectators (at 43% capacity).
That Juventus was indebted to goalkeeper Gigi Buffon, whose early save from Yannick Ferreira-Carrasco was important, will give the host some hope; and it has upped its scoring rate since getting past Arsenal last month. Monaco has also leap-frogged Marseille in the race for third place and a spot in next season's Champions League qualifying stage.
For Juventus, it will be an emotional return for 33-year-old Patrice Evra, who burst onto the scene as part of the 2004 Monaco side that beat Real Madrid and Chelsea in reaching the Champions League final. Even then, there was very little atmosphere around the Principality to mark the occasion. This Monaco plays a more pragmatic style, but it could be just as big a shock if it knocks out the Italian champion.
GALLERY: Best tifos around the world
Best soccer tifos from around the world
Galatasaray fans display a sensational "Rocky" tifo ahead of their clash against rival Fenerbahce. It didn't inspire a victory, though. The Turkish rivals played to a 0-0 draw.
Borussia Dortmund fans channel their 1963 cup triumph over Benfica ahead of the teams' second leg in the Champions League round of 16 at Signal Iduna Park.
Hapoel Be'er Sheva fans turn to Moses for tifo inspiration, with his splitting the Red Sea illustrating how "impossible is nothing" in their Europa League series against Besiktas.
Fans of Tunisia's Club Africain display this pointed tifo at a friendly against PSG, whose Qatari owners have pumped millions and millions into the club.
U.S. fans in Columbus, Ohio, make a "One Nation, One Team" statement ahead of the USMNT's World Cup qualifying match against Mexico on November 11, 2016.
Germany fans display their heart for the team colors ahead of a World Cup qualifier against Czech Republic in October 2016.
Italy fans spell out their support for the Azzurri ahead of a massive World Cup qualifier vs. Spain in October 2018.
Iceland fans keep up their world-famous passion for the national team during a World Cup qualifier against Turkey in October 2016.
Fans in the United Arab Emirates set their sights on reaching the 2018 World Cup in Russia during a qualifying match vs. Australia in September 2016.
Colombia fans send a massive jersey around the stadium during a World Cup qualifier vs. Venezuela in September 2016.
Seattle Sounders fans turn to Game Of Thrones for inspiration in a game against the Cascadia rival Vancouver Whitecaps in September 2016.
Djurgardens fans go all out in Sweden for a match against AIK in September 2016.
Zulte Waregem fans prepare Kortrijk for the absolute worst in this Belgian top-flight match in September 2016.
Seattle Sounders fans turn their pop culture reference to Poltergeist in March 2016 ahead of the season home opener against Sporting Kansas City.
The Timbers Army doubles down on their Eastbound and Down theme, adding another wrinkle during the club's MLS Western Conference final first leg vs. FC Dallas on November 22, 2015 at Providence Park.
Fans make a French flag tifo at Wembley Stadium during the singing of Le Marseillaise ahead of England's friendly vs. France, which took place days after the terrorist attacks in Paris.
The Timbers Army referenced Eastbound & Down's Kenny Powers with their "Cup Bound and Down" tifo for the Portland Timbers' MLS playoff elimination game against Sporting Kansas City on October 29, 2015.
Brondby IF fans display a gladiator holding up a lion's head during the team's Danish Alka Superliga match against FC Copenhagen, whose logo is a lion's head, on September 27, 2015.
New England Revolution fans equate Jermaine Jones to Indiana Jones on their quest to capture the 2015 MLS Cup on September 26, 2015.
New England Revolution fans display a Lion King theme in honor of Orlando City FC's first visit to Gillette Stadium on September 5, 2015.
Red Bulls fans take a shot at NYCFC's two summer arrivals, 37-year-old Frank Lampard and 36-year-old Andrea Pirlo, ahead of their third MLS meeting of 2015.
Germany fans in Cologne salute their World Cup champions ahead of a friendly against the United States in June, 2015.
Real Madrid fans went all out prior to the second leg of the 2014-15 Champions League semifinal vs. Juventus.
Lazio fans display a stunning eagle tifo ahead of the Rome derby against AS Roma in their penultimate Serie A match of the 2014-15 season.
Barcelona fans bid farewell to veteran midfielder Xavi with this banner at his last league game at Camp Nou before he departs for Qatari club Al Sadd.
Fans at Anfield pay tribute to Steven Gerrard in his final home match as a Liverpool player in May 2015.
Juventus fans state their case to beat Real Madrid in the 2014-15 Champions League semifinals and reach the final in Berlin.
Fans at Benfica's Estadio da Luz remind rival Porto who the Primeira Liga reigning champion is during an April 2015 match in Portugal.
New York Red Bulls fans send a pointed message to their NYCFC counterparts prior to the teams' first MLS meeting in May, 2015.
Inter Milan's Curva Nord announces its presence ahead of the April 2015 Derby della Madonnina–the annual clashes between city rivals Inter and AC Milan.
Bayern Munich fans implore their club to (translated) "Never give up" in the Champions League quarterfinal second leg vs. Porto. Bayern then turned a 3-1 first-leg deficit into a 7-4 aggregate win and a place in the semifinals.
Dortmund fans commemorate their 1997 Champions League trophy in the club's clash vs. Juventus–the opponent on the wrong side of that title bout.
Portland Timbers fans speak out against homophobia with this tifo in a 2013 match against Chivas USA
Atletico's supporters display a banner reading "Atleti crushes" before the Spanish league match between Atletico Madrid and FC Barcelona at the Vicente Calderon stadium in Madrid,
Borussia Dortmund fans put on a remarkable display ahead of a UEFA Champions League quarterfinal second leg match.
Brondby IF fans unveil a tifo ahead of a match in Denmark against Randers FC.
FC Barcelona fans display a huge banner in memory of former head coach Tito Vilanova.
Galatasaray fans support their team during the UEFA Champions League Group D match between Borussia Dortmund and Galatasaray at the Turk Telekom Arena in Istanbul.
The American Outlaws unveil a huge tifo ahead of a 2014 World Cup send-off match between the USA and Turkey at Red Bull Arena in Harrison, N.J.
Marseille's supporters use paper sheets to create an "OM" (Olympique de Marseille) tifo at the beginning of the French L1 football match between Marseille and Genoble.
Seattle Sounders fans display their tifo that shows coach Sigi Schmid playing cards and holding a Royal Flush before a match against the Portland Timbers.
Panathinaikos Athens fans display a banner during the UEFA Europa League match against Dynamo Moscow.
Fans of the Saudi Al-Hilal team celebrate after the scoring of a goal against Uzbekistan's Bunyodkor.
Seattle Sounders fans unveil a tifo inspired from the “Build a Bonfire” chant, featuring Sounder players holding torches on horseback ahead of a game against the Portland Timbers.
Fans of Hertha BSC before the Bundesliga match between Hertha BSC and Werder Bremen in Berlin.
Sporting Kansas City fans channel their inner Mario ahead of the 2013 MLS Cup final vs. Real Salt Lake.
Brondby IF fans.
Thousands of Barcelona fans hold up cards to spell out "Barca! Orgull," which translates to "Barcelona pride" ahead of a Champions League clash with Bayern Munich at Camp Nou.
Fans raise a tifo celebrating “Community, Club and Country” ahead of a CONCACAF Gold Cup match between the USA and Belize in Portland, Oregon.
Vitesse fans unfurl a massive Eagle banner at the Dutch Eredivisie match against Ajax at the GelreDome.
Valencia fans drape a banner featuring a king for a Copa del Rey ("The King's Cup) match against Atletico Madrid.
Juventus fans make a statement in Turin in a match vs. Inter Milan.
Dortmund fans put on another strong display at a Bundesliga match against Mainz 05.
German fans boast the newest star earned by the national team, symbolizing its 2014 World Cup triumph, at a Euro 2016 qualifying match in Dortmund.
Real Madrid fans make a point to display the club's 10 European championships ahead of the October 2014 clash against rival Barcelona at the Bernabeu.
San Jose Earthquakes fans unleash a massive tifo to mark the opening of Avaya Stadium, MLS's newest soccer-specific venue, in March 2015.
Barcelona fans show all who the real 12th man is ahead of the March 2015 Clásico vs. Real Madrid.
Ahead of a clash with Mexican foe Monterrey, Tigres players are treated by this message by its fervent supporters.
Standard Liege fans have a pointed message for Steven Defour, who departed the club for Belgian rival Anderlecht.
Orlando City fans mark their club's inaugural MLS game vs. fellow expansion side New York City FC with a statement that the Lions' "reign begins now."
Real Madrid fans salute Ballon d'Or winner Cristiano Ronaldo after he captured the most prestigious individual prize in world soccer again.
Vitesse fans pay homage to Operation Market Garden ahead of an Eredivisie match against SC Heerenveen.
Sevilla's fans deploy a giant banner in the stands before the UEFA Europa league final match between Benfica and Sevilla.
Fans in Liverpool’s Kop End at Anfield commemorate those lost in the Hillsborough disaster.
Lyon fans during a game against Saint Etienne.