Manchester United striker Wayne Rooney says he can't explain his World Cup flop.
Rooney admits the ball was a concern for him.
He said: "I prepared well for it. We prepared well as a team and once we got on the pitch it just didn't click. So it still, to this day, puzzles me. I can't really say I wasn't fit, as I trained every session with the team before the games.
"I'm not using the ball as an excuse, but the ball wasn't up to the standards to be the World Cup ball. Me personally, I knew I wasn't playing well, and sometimes then you try to do too much instead of keeping it simple.
"And once it happens in a couple of games, and you're thinking am I going to play well, am I going to score a goal? And it drags on, but I'm extremely disappointed with it, and I'm sure the whole of the country is, because they expected more."
Sir Alex Ferguson was criticised for playing Rooney during the final weeks of the season when he was carrying the injury.
But Rooney added: "I think I was fine. I just can't see why I didn't perform - not even to half the performance levels I know I can do."