Manchester United captain Roy Keane has warned the club's young players not to take things for granted at Old Trafford.

"We have worked extremely hard to get to the top but it is a lot harder to stay there," the 32-year-old midfielder said on Friday.

"We have one or two young players who have done very little in the game. They need to remember that and not slacken off.

"They need to remember just how lucky we all are to play for Manchester United and show that out on the pitch."

Manager Alex Ferguson has made signing young players a priority this season as he looks to maintain United's domestic dominance.

But the Premier League champions have stuttered in recent weeks to fall five points behind Arsenal in the title race.

Keane will return to lead United in Saturday's FA Cup derby with Manchester City after being rested for their mid-week 3-2 home league defeat by Middlesbrough.

The former Republic of Ireland international is a three times winner of the Cup with United and is determined to get past visiting City and into the quarter-finals.

"The fact there will be 9,000 City fans there should ensure a brilliant atmosphere," Keane added.

"Results-wise, they aren't having a good time of it but I know one or two City fans and they say the performances haven't been that bad.

"There is a fine line between playing well and winning football matches and I'm sure City will be confident, especially when they look at the goals we have been conceding.

"But we are determined as well. The disappointments we have had in the FA Cup in the past few years make the competition more important to us than ever this season."