#1 Who else but Lionel Messi
There are some things that are meant to happen, that are inevitable. Lionel Messi scoring the winning goal for Barcelona is one such phenomenon. It is not that Barcelona lacked chances to score before Messi came in. Coutinho had Levante at the ropes on more than one occasion.
Dembele could have scored when he dribbled past everyone but he chose to pass instead. Vidal's shot could have gone in but it was blocked by the defender. But when the ball fell to Messi, the seemingly unbreakable defense was completely out of position. The unbeatable Aitor Fernandez could not get a hand strong enough to deflect the ball away. That's why we say, these are things that are meant to happen.
Lionel Messi promised us that he will try and deliver the Champions League to the Camp Nou. The top-scorer in the UEFA Champions League right now, the European Golden Boot frontrunner, but never scored against Liverpool. There were things that he hadn't done before on a lot of Champions League games, scoring against Chelsea, scoring against Cech, Buffon, but he ended up doing all those.
Would you bet against him scoring against Liverpool? Sorry, we won't.