He was the best player in the first half if you value a forward who is all work rate, but totally incapable of being even a remote scoring threat. Alexis in the first half played like a wide midfielder, not a forward. His hard work rate is admirable, but I need my forwards to be scorers and scoring threats first and foremost. Unsurprisingly he was totally spent in the second half and his already low scoring threat turned into a nonexistent one.
Seriously, Barca's wingers total inability to threaten the goal is completely disrupting the offensive flow. Teams can just compact the middle and totally snuff the midfield and poor Messi who is being completely blanketed by at least 3 players. Every time he received the ball he had at least one player nipping at his feet.