Manchester United defender Rio Ferdinand admits fighting for title can leave him an "emotional wreck".

The world's most expensive defender regards his two Premier triumphs at United as the peak of his career.

"It's what you play for the whole season - busting a gut, sweating, the ups and downs," said the England centre-back. "You're an emotional wreck, especially when every game means something.

"During the last two or three months of last season, it was all cup finals. To emerge from it to say that you're the best team in the league is such a feeling."