Zlatan Ibrahimovic headed it down, and with the last kick of the match, Blaise Matuidi fired Paris Saint-Germain level.
A slight deflection took it past Victor Valdes, but PSG won't care. They had their equalizer and, with it, some hope to carry forth to Camp Nou next week.
The French side accelerated out of the blocks, but, as ever, it was Lionel Messi who opened the goal scoring with a wonderful finish.
Ibrahimovic squared the score in the second half, but when Alexis Sanchez won a penalty and Xavi Hernandez converted it, Barca looked set to clinch the win.
But in a final twist, Matuidi popped up to keep things even ahead of the second leg.
Here are Barcelona's winners and losers from their night in Paris...
For nearly 40 minutes, he slipped by relatively unnoticed.
Then one sumptuous pass from Dani Alves put him behind the PSG defense, and he finished like the expert that he is with his first touch.
It was the seventh goal Barcelona had scored away from home in the Champions League this season—the Argentinian had scored three and set up two of the previous six as well.
Five minutes later, he nearly scored the eighth. Cutting in onto his left foot, he fizzed a curling effort just wide of the PSG goal.
Unfortunately, minutes later he went from winner to loser:
Messi sustained an injury to his right hamstring. He will undergo further tests on Wednesday to determine the extent of the injury. #FCBLive— FC Barcelona (@FCBarcelona) April 2, 2013
This has happened before: He went off injured against Benfica in December, and panic set in at Camp Nou. But by the weekend, Messi was fit to feature against Real Betis.
La Blaugrana will hope it's a similar case this time.
Even if he did nothing else for the whole 90 minutes, his assist for the Lionel Messi goal makes him a winner on its own.
Check it out here—seriously.
Javier Mascherano provided Barcelona with a double blow tonight.
Firstly, he picked up a yellow card—a caution which means he will be suspended for the second leg at Camp Nou next week.
Then, inside the last 10 minutes, he injured himself and was replaced by Marc Bartra.
With Carles Puyol already on the treatment table, the last thing Barca needed was more injury woes in defense.
UPDATE: It's already been revealed Mascherano will be out for six weeks:
Six weeks for Macherano.... Blimey, virtually no defence— Sid Lowe (@sidlowe) April 2, 2013
Check out who's back in the Barcelona dugout.
Last week he flew back home to Catalonia following cancer treatment in New York, and on Tuesday night he was back in the Barca bench.
“I’m very pleased with his return," said Cristian Tello.
"We need him. His absence was noticeable because the presence of the head Coach is always very important.”
In a way, the result against PSG was always going to be secondary, because with Tito back at the helm and Eric Abidal back around the club, La Blaugrana already had plenty of things to be happy about.
In Monday morning's Mundo Deportivo, it was predicted that Cristian Tello would get the nod alongside David Villa and Lionel Messi in Barcelona's front three.
The 21-year-old was wonderful against Celta Vigo on Saturday night and would have been full of pace and confidence at Parc des Princes.
It wasn't to be, though, and the youngster had to make do with a 10-minute cameo at the end in place of David Villa.
Speaking of Villa, for the second week running the Spanish forward endured a quiet night in the French capital.
The look on Victor Valdes' face said it all.
"I'm going to cop the blame for this."
Unfortunately in the world of goalkeeping, and for some reason even more so in the world of Valdes, mistakes are magnified.
Truth be told, it was barely a mistake. However the moment Blaise Matuidi's deflected shot crept in, the ridicule began:
The way Victor Valdes went down then reminded me of Willem Dafoe on the cover of Platoon.— Tony Barrett (@TonyBarretTimes) April 2, 2013
It's a shame.
Two great stops from shots by Zlatan Ibrahimovic and one from Javier Pastore may be largely forgotten in the aftermath of that goal.