I thought he was clearly in front before the ball was passed; the only question was whether he ran into the defender, or if the defender went to him. A yard to the right and he'd have been okay, I think.
He was slightly ahead but people overrun the ball and catch legal passes that go behind them all the time. For it to be crossing he has to have no chance of taking the pass.
Let's just say I dont think it gets called at the other end of the pitch...