He didn't touch the ball once though. Barce kept feeding him the ball, and most of the time his attempts to unlock the defense failed. He's a great player, but he still has matches where he doesn't play that well. More often than not he ended up giving the ball away last night and handing possession straight back to Milan. The fact that they weren't able to do anything with it doesn't detract from the fact that on an individual level Ronaldinho didn't have a great game.
I'd say it's the other way round. While Villarealy did well to knock out Inter in the last round, Arsenal have beaten (and to a large degree outplayed) much better sides, such as Real Madrid and Juventus.
