Did anyone predict the drama that unfolded in last week's Champions League knockout games? Holder Real Madrid thought it was through after a comfortable first-leg away win but was left hanging on after losing 4-3 to Schalke. Chelsea was a favorite after a 1-1 away draw in Paris, and looked certain to go through after PSG has Zlatan Ibrahimovic sent off after half an hour, only to lose on away goals in extra time to the French team at Stamford Bridge.
If this week's match-ups provide half the excitement, then it should be a fascinating couple of days in Europe's top competition.
Here is how Tuesday and Wednesday's second legs shape up, as the remaining four quarterfinal tickets are slated to be punched:
Tuesday, March 17
Atletico Madrid (0) vs. Bayer Leverkusen (1)
If FC Porto is a dark horse already in the quarterfinal draw, what does that make Bayer Leverkusen? Under coach Roger Schmidt, who has been singled out by Pep Guardiola as a coach he greatly admires, the German side out-Atletico'd the Spanish champion and a 1-0 first leg win leaves it well-placed for progression. Hakan Calhanoglu took the plaudits for his super game-winning goal–only last week his agent admitted that Barcelona was interested in the midfielder, but he was happy in Germany–but Gonzalo Castro embodied the Leverkusen approach.
The experienced midfielder, whose parents are Spanish, is a one-club man, and at only 27, this game will be number 350 in his Leverkusen career. As he posted on Facebook in 2013, after celebrating a record for Bundesliga appearances aged 26, he wrote: "234 games, 10 different positions, but one team."
He is now settled in midfield, but Bild calculated he had spent 146 games out of position, either in defense or on the wing. He believes there is an anti-Leverkusen conspiracy at international level.
A former teammate of Manuel Neuer, Mesut Ozil and Mats Hummels in the victorious 2009 Euros Under-21 side, he told 11 Freunde: "Maybe I'd be in the national [team] if I had changed clubs."
After Schalke confounded expectations with a top European performance and four goals in Madrid last week, will Leverkusen repeat the feat of its fellow German side? Atletico's Liga target this season is third place, judging by Diego Simeone's response to recent draws with fourth and fifth-placed sides Sevilla and Valencia, but after four games without a win, and no goals from his strikers in that period, Atletico is not on form. Based on the first leg, it was Leverkusen who looks the more likely to advance.
Monaco (3) vs. Arsenal (1)
Some of Arsenal's best recent performances in Europe have come when the odds are stacked against the club. The Gunners beat Bayern Munich 2-0 at the Allianz Arena in March 2013 but had lost the first leg 3-1 and so was eliminated on away goals. Then there was season before that, a fantastic 3-0 second-leg win against AC Milan, with all the goals in the first half. Again, not enough to go through: Milan had won 4-0 a few weeks earlier.
Arsenal and first-leg European brain freezes are nothing new; what is so surprising about last month's 3-1 home loss to Monaco was that it came out of nowhere. Arsenal had won eight of its last nine games before the Monaco match, and has won its four matches since then. Rather than obsess about what happened, coach and players have insisted they can turn it around in Monaco. They say this despite Monaco's defensive record, which is the best in France (20 goals conceded in 28 games) and in Europe (two goals conceded in seven games).
At home, its even better: only one goal conceded in its last 12 matches at Stade Louis II (and that was a Cup match, a 3-1 win over Rennes). Perhaps most impressively of all is that coach Leonardo Jardim has not been able to pick a settled back line during that time: Tunisian Aymen Abdennour was at the African Cup of Nations and Wallace had a six-match suspension, while Layvin Kurzawa, Ricardo Carvalho and Andrea Raggi have missed a combined 25 weeks out through injury.
Carvalho played for the first time in five weeks on Friday night, and has insisted he is ready for the Arsenal game. Arsenal needs to score three goals, at least, in Monaco. The last time Monaco conceded that many in this competition, it was in 2004, the season it reached the final: it beat Deportivo la Coruna 8-3. Don't expect a similar result this time around, but it will be entertaining watching the Premier League side go for it.
Wednesday, March 18
Barcelona (2) vs. Manchester City (1)
It doesn't take long for a blip to become a crisis, and Barcelona has shown that it can work both ways. A basket case in December, with neither Lionel Messi nor Luis Enrique certain to stay past the summer, now the team is top of La Liga, and Messi is ahead of Ronaldo in the Pichichi table for top goal scorer (closing a gap of 12 goals in the last 10 games) and back in the kind of form that would scare any defense, let alone one that has just lost to Premier League relegation candidate Burnley.
In fact, when the pressure on Enrique was at its height, Manuel Pellegrini was touted as a possible replacement. Now, speculation is swirling over the future of Pellegrini in Manchester, with another title defense failing and City facing a huge task in Barcelona after it was totally outplayed at the Etihad three weeks ago.
In the first leg, Luis Suarez took the plaudits with both goals in his first game back in England, and along with Messi and Neymar, the front three are closing in on a record goals tally. At the moment the three have 82 goals combined, just 19 goals short of the 101 total that Messi (38 goals), Samuel Eto'o (37) and Thierry Henry (26) combined to score in 2008-09, the season in which Barcelona won all six competitions it entered.
Barcelona has 11 Liga matches, one Copa del Rey final and, you would imagine, at least two more Champions League ties after this one to play–although Messi's penalty miss at the end of the first leg has left the door cracked ajar for City to make it interesting.
Borussia Dortmund (1) vs. Juventus (2)
Can Dortmund really get over its mediocre domestic season and conjure a run deep in the Champions League? It has been a knock on coach Jurgen Klopp, albeit a harsh one, that this side can't combine domestic and European form. Saturday's goalless draw against FC Cologne was more like the old days from earlier in the season, at least without the defensive howlers.
Perhaps the players' minds were on this game, but Marco Reus looked like a player who was rushed back from injury, while Henryk Mkhitaryan limped off with a nasty-looking knee injury. Dortmund has been Jekyll and Hyde all season and it must be infuriating for Klopp; when it's good, it is very good.
The news is more positive for narrow first-leg winners Juventus, which welcomed back Andrea Barzagli over the weekend after nine months out with an Achilles injury and was indebted to sub Alvaro Morata's winner at Palermo to move 14 points clear at the top. "Borussia, we're on our way!" ran the Tuttosport headline while coach Massimiliano Allgeri, who has already improved on his predecessor's European return last season (group stage failure) needs to decide if Barzagli is ready for such a big game so soon.
The fact is, for all the genius of Andrea Pirlo and Paul Pogba in Juve's midfield, this tie could turn on the simple issue of which Dortmund decides to turn up.