Manchester United manager Sir Alex Ferguson has started his preseason motivational campaign early by demanding his players prove their hunger for success.

By their own high standards, United had a poor season last time, finishing third in the English Premier League and failing again to reach the Champions League final.

A series of defeats early in the season spoiled their chances of retaining the Premier League title and raised questions about the players' ability to raise themselves on a regular basis after a sustained period of success.

Ferguson, who would have been watching the coming season from his armchair had he not changed his mind about retirement, hopes that the empty trophy cabinet will spur the team into even greater efforts.

"The disappointment of winning nothing will have a positive effect," he was quoted as saying in Saturday's Daily Mirror.

"This has been the first time in 10 years we have finished outside the top two. Maybe it'll be the kick up the backside we needed because I'm certainly not accepting it.

"We are going to have to do something about it."

Ferguson, who is being linked with a move for Leeds United's England centre back Rio Ferdinand, says he has no doubts about the quality of his squad -- just their attitude.

"You have to say the only thing to worry about, with the ability we have here, is desire," he said.