Sir Alex Ferguson claims the young stars who won him his ninth Premier League title last month have given him the appetite to carry on in his Old Trafford role indefinitely.

The 65-year-old Manchester United manager will prepare to embark upon his 21st season at the helm in August without showing any inclination whatsoever of easing into well-earned retirement.

"There will be a time when I retire but when that is I have absolutely no idea," Ferguson said. "Young people help you and I've got some good young players at the club, and good personalities. Cristiano Ronaldo and Wayne Rooney are fun to watch in training with all their tricks and their double act, and I think that helps keep you young."

Ferguson was due to retire at the end of the 2001-02 season but reversed his decision during the campaign, agreeing to stay for at least another three years. "As long as my health is good that is a consideration, without question," he said. "But I feel good and I think that is the determining factor to carry on."

Ferguson's bid for a tenth title next season received a double boost when Alan Smith pledged his future to the club and Ole Gunnar Solskjaer played down a new injury scare.

Smith insists the £40 million signings of Anderson, Nani and Owen Hargreaves last week have failed to convince him that his future is anywhere other than Old Trafford.

Smith, who is reportedly on the wanted lists of Everton, Tottenham Hotspur, Middlesbrough and Sunderland, said: "I have a contract re-negotiation coming up. I was due contract talks last year and we decided, the club and myself, that I wouldn't do that when I was injured, because it wasn't fair on them. But now I am fit and ready to commit my future. I want to stay at United. My agent has spoken with the club and the talks should happen in the next few weeks."

Meanwhile Solskjaer insists he will bounce back from his latest bout of surgery on the same knee which has required major reconstructive surgery in recent years. The Norwegian went back under the knife last weekend after reporting discomfort whilst training, but is expected to be able to return to full training within a matter of weeks.

"I don't want you to write my football career history book yet," Solskjaer said. "I was relieved to discover that this wasn't new, but something from the injury in March. Physically and mentally I'm ready to join the team at the start of the season in four weeks."