When that ball went past Victor Valdes in the 94th minute yesterday, it changed the face of this fixture.
Barcelona was about to walk out of that match with a goal advantage, but Blaise Matuidi's late effort deflected past Valdes.
Now, Paris Saint-Germain will head to the Nou Camp on level pegging.
Well, technically not.
Barcelona has the advantage with two away goals, so regardless, Carlo Ancelotti's men will need to score. But Tuesday's match showed that PSG has the ability to get past Barcelona and into the semifinal of the UEFA Champions League.
To be fair, the French team did not play all that well and probably did not deserve either of the two goals it received. Zlatan Ibrahimovic was clearly offside on the first goal and Matuidi's shot got through because of poor defense by Barca.
But PSG can play better than it did yesterday and will hopefully bring its best when the two sides face off again next Wednesday.
Barcelona has stated that Lionel Messi will miss this weekend's match against Mallorca but have not ruled him out for the second leg against PSG as yet. My guess is that he will be back for the second leg, but I'm not a doctor so don't take my word for it.
If Messi is playing next week, though, the key would obviously be to minimize his effectiveness.
Yesterday, PSG did a great job with Xavi and Andres Iniesta. David Beckham and Matuidi closed in on the two, which forced Messi to drop back further to get the ball. This took Messi out of his comfort zone a bit, which in turn helped PSG. In most cases, if you shut down Xavi and Iniesta, Messi becomes more manageable.
But should Messi be absent in the second leg, PSG will stand a better chance at moving on to the next round.
Messi has eight goals in the Champions League, which ties him at the top of the goalscoring list with Cristiano Ronaldo and Burak Yilmaz. But without Messi goals, not many other players are picking up the slack.
Barcelona is still a strong squad, but it does not have the same effectiveness that it has had over the past few seasons.
I'm not saying that PSG is a better squad than Barca, but it can certainly get past the Catalan giants. With injuries and the poor form of several players, Barcelona can be defeated at the Nou Camp.
Barcelona's defense is also suffering. When April 10th rolls round, the only healthy centerbacks will be Gerard Pique and Marc Bartra.
While Pique will most likely be effective, Bartra is young and lacks experience. It will be interesting to see who Tito Vilanova puts on his back line..
The French side will have the upper hand come next week, especially if Messi is out.
PSG will do well to take advantage of Barca's weaknesses.
The tide may have turned in the French's favor, and they very well could walk out of the Nou Camp with a ticket to the next round if they can take advantage of Barcelona's weakened state in the second leg.