Messi's arrival lifted his whole team. He may only have been 50 percent fit with his hamstring injury, maybe even less, but he made the difference. It was his jinking run and pass for David Villa to cut back to Pedro for the equalizer that sent Barcelona into its sixth straight semifinal.
Barcelona was not only missing Messi but also missing Carles Puyol and Javier Mascherano. All three absences showed, as it squandered chances in front of goal, looked vulnerable from set pieces, and with Adriano shaky alongside Gerard Pique in back, conceded space and opportunities, too.
When PSG's Javier Pastore broke the deadlock five minutes into the second half, the surprise was not that Barcelona, unbeaten at home in this competition since February 2007 (when Craig Bellamy celebrated his goal with a golf swing), was facing a knockout, but that the visitors, so brave up to then, had not scored earlier.
Barcelona had 13 shots in the first half, none of which were on target, the first time this season it has failed to test the goalkeeper in 45 minutes. But PSG had looked more likely to score, even if Xavi brushed the side-netting with an early free kick and Andres Iniesta tried his luck with an audacious 40-meter lob.
Barcelona's Victor Valdes had been the busier keeper, stopping Ezequiel Lavezzi in a one-on-one with his feet, and diving sharply to parry Lucas Moura's header. Both chances had been created by Zlatan Ibrahimovic, whose build-up play was brilliant throughout. It was his pass, in fact, that released Pastore to chip the ball over Valdes in the 50th minute for a deserved lead.
It was symbolic that Pastore was the scorer; he was the first player sports director Leonardo signed for PSG, aged 21 and at a cost of ?42 million. It was always going to be hard for him to make his mark, and there were times last season when he struggled.
"He's not Messi, he's not Iniesta, he's not even [ex-PSG player] Rai," Lyon's sports director Bernard Lacombe told
But if Pastore was the scoring hero, the star man for PSG, at least in the first half, was winger Lucas Moura (the last player that Leonardo signed). It was somehow appropriate that Lucas was so dangerous at Camp Nou, where Barcelona's sponsor is the Qatar Foundation. This match had been nicknamed the Qatar Derby, and it brought back memories of Lucas' official unveiling as a PSG player in Doha in January.
PSG needed to sort out visas for Lucas and his family to come to Qatar, and sports director Leonardo asked his agent, Wagner Ribeiro, to email passport copies over. He added a text message, reported ESPN Brazil, via WhatsApp, that read: "No problem. In Qatar, we make the law."
You also wondered what Manchester United coach Sir Alex Ferguson thought as he watched Lucas skip past Jordi Alba like he wasn't there. "I find it unbelievable that a club can pay ?45 million for a kid of 19," Ferguson told
And yet the match-winner cost Barcelona nothing and was fast-tracked into the first team by Pep Guardiola, who didn't want to sign Fernando Torres because he knew Pedro was waiting in the wings. Sure enough, in Guardiola's record-breaking first season, in 2008-09, Pedro made history as the only player to score in the league, the Champions League, the European and Spanish Super Cups, the Copa del Rey and the World Club Cup, in the same campaign.
"If Pedro was Brazilian," Guardiola once said, "he'd be called Pedrinho and we wouldn't have enough money to afford him."
PSG leaves the competition with its head held high, having given notice of its credentials as a serious player on the pitch (UEFA's financial regulations notwithstanding). The PSG project is alive and well, and the fact that everyone in France was talking about this game -- in stark contrast to 2010, when Lyon reached the semifinal and it barely registered -- shows how far it has come in a short time.
"With Zlatan, Paris can become the new Chelsea of European football," the Swedish striker's former Malmo coach, Ola Gallstad, told
Meanwhile, Barcelona breathes a huge sigh of relief and wraps up Messi in cotton wool until the semifinal comes around.
That might become part of the post-mortem in Turin, though the truth is that Juventus played far better than it did in Germany eight days ago, and still fell short. It had chances, but no one to get on the end of them; perhaps this match was best summed up by the excellent first-half move that released Paul Pogba down the right, only for his fizzing cross along the six-yard line to met by not a single Juventus striker.
Juve boss Antonio Conte had spoken before the game of the faith he had in his bosses and their market moves. One of those decisions was to not splash out on Didier Drogba in January; or to bring forward Llorente's Juventus move six months. Since the turn of the year, the Spanish forward has played nine games for Athletic Bilbao, eight as a sub, and scored no goals. Anelka, by the way, has played 25 minutes since his January move.
Bayern has showed the value of a decent goal scorer all season, and one surprise is that it has been Mario Mandzukic and not last year's hero, Mario Gomez. Bayern boss Jupp Heynckes loves Mandzukic for his all-round play, and his dead-eye in front of goal was apparent when he pounced quickest on a Gianluigi Buffon parry to prod Bayern ahead in the 64th minute.
The Croatian had already been booked and will miss the first leg of the semifinal. No matter; late substitute Claudio Pizarro, who scored four goals in Bayern's 9-2 win over Hamburg 10 days ago, came off the bench to double the lead in injury time. Bayern beat a below-par Juventus last week and a strong Juventus this week.
It takes its place in the semifinals alongside the three other best teams in Europe at the moment. That's rare to see in a knockout tournament and why this year's competition is unique and all the more compelling. You could argue a case for any of the teams in the last four to win it, and that's how it should be.