The Champions League kicked off with a bang this week, featuring 16 enthralling matchups with the best sides in Europe doing battle.
There were some epic comebacks. There were some thrilling collapses. There were some dull battles. It was quite a start to what should be a thrilling season of Champions League football.
With so much of the season still ahead of us, it would be unwise to draw too many conclusions from the teams' first matches. On the other hand, it is clear that some questions should be raised about some of the top clubs after their first match.
So what should we be asking ourselves about the upper echelon of the Champions League heading into the rest of the competition?
Here are the four biggest questions.