A lot of people are slamming this ref. Think about this for one moment:
If the ref had waited before he blew the whistle and the ball had gone to Ludovic Giuly as it did. Then Giuly had missed!! Once Giuly takes posession of the ball the advantage has been realised and so then the ref cannot take it back. If Giuly had missed all he could have done was to Give Lehman a yellow and gone with a goal kick if the ball had gone wide.
Is that fair to Barcelona?? They would have said that Lehman should have gone and they got robbed.
The ref didn't know what would happen once the ball went to Giuly. In this case he scores and everyone is on the ref's back.
But he could have missed and I think Lehman deserved more than a yellow for what he did.
The ref did the right thing.
Blame Lehman for doing such a stupid thing so early in the game.