Watch Barcelona pull off the most unbelievable comeback in Champions League history

Barcelona lost the first leg of their Champions League round of 16 tie against Paris Saint-Germain, 4-0. They were dead and buried.

The problem is no one told Barcelona that, so they came out firing and cut the PSG lead to 2-0 before halftime.

Then, just minutes into the second half, they had a third.

All of a sudden, Barcelona were only down a single goal on aggregate. They had their chance.

Only Edinson Cavani snatched it away from them. He scored, not only making the deficit two, but giving PSG an away goal. Barcelona now needed three more goals.

Barcelona were dead and buried. Again.

And that was still the case in the 88th minute. Two minutes plus stoppage time to score three. It was over.

Only ...

It started with that gorgeous Neymar free kick. It was amazing, but bound to be forgotten. Who was going to care about a goal from the team that was getting eliminated, after all?

But then Neymar scored another on a penalty kick in the first minute of stoppage time. Maybe a comeback was possible?

Betting on Barcelona to score a goal in four minutes is reasonable. At this point, the comeback was in the realm of possibility. But come on, you couldn't separate this last goal from what had happened to this point.

Coming back from 4-0 down was going to pale in comparison to scoring three goals in the last seven minutes. Somehow, Barca were on the verge a comeback that made "down four goals" look easy.

And that's the comeback they pulled off thanks to Sergi Roberto.

It was done.

From 4-0 down. From three goals down with seven minutes to play. From the dead.

Barcelona pulled it off. They did what no one believed they could do. What no one had ever done in the history of the Champions League. They did the impossible.