Manchester United manager Alex Ferguson has backed captain Roy Keane's decision to consider playing on past his planned retirement date. Keane (33), had intended to end his playing career when his current contract at Old Trafford expires in June, 2006.

But Keane now says he is tempted to play beyond that date if he is still fully fit and still required by the club he joined from Nottingham Forest in 1993.

"I'm not surprised the way he's playing. He's in fantastic form," Ferguson said yesterday.

"It's his best (form) of the season. He's really come to the forefront of his game. And in that form, if I was him, I would want to stay on playing too."

Ferguson jokingly suggested if he was playing as well as the midfielder, he would ask for a new contract too.

Keane has helped United win five of their last six games to get within nine points of premier league leaders Chelsea going into the important Christmas period.

United play Bolton, Aston Villa, Middlesbrough and Tottenham and Ferguson expects his side to come out the other side well placed in the title race.

"It's the start of the run-in. When you're through December there are sometimes casualties in terms of teams dropping points you don't expect," he said.

"What pleases me is that our form has hit at the right time. When we get through this period to January 4th after the Tottenham game, there is the FA Cup to follow and we can assess where we are and where the whole league is and hopefully we're right on the tails of the leaders. There is a great consistency in our performance. What we want now is consistency of results. In the run-in, as is proven over the years, we make less mistakes after New Year than we do before it."

Keane will now look to justify an extension to his contract, which expires in 18 months' time. He will turn 35 in the summer of 2006, and the hip injury which has blighted his game over recent seasons had led many to believe he would retire upon the expiry of his present deal.

However, after his recent good form he is optimistic his Old Trafford career could still have several years to run.

"I could not be happier at the club and my biggest challenge is to keep going as long as I can," Keane told the Daily Mail. "I have another year and a half left and I intend to see that out. If I am still able to play on after that, then I hope it will be at United.

"If I feel as good as this physically in a year's time, then I will hopefully try to play on."

Keane recognises that any decision is out of his hands, however, his long service could persuade United to reward the skipper with an extension.

"As long as United want me, then I'm happy to stay," he added. "I don't like looking too far ahead as things can change quickly.

"But if, please God, I can stay fit and feel strong and doing okay, then it's possible I could stay.

"I hope that there will be some more highlights to come in my career with this club."

Keane hopes a more controlled attitude on the field will benefit his team-mates.

He has had his fair share of scrapes and disciplinary problems during a 14-year career in England but his last red card was in February during the Champions League defeat in Porto.

And although he has accumulated five cautions this season, the combative midfielder is convinced he will no longer be drawn into the kind of rash actions which frequently saw him sent off.

Keane, infamously, exacted retribution on Manchester City midfielder Alf Inge Haaland after his opponent had falsely accused him of feigning injury several months before.

However, that kind of recklessness is no longer part of Keane's make-up.

"As you get older you learn to try to relax a bit more," he explained. "If a certain player does wind me up and I focus on that one individual I realise I am taking myself away from my own team.

"If there is a ball there to win I will go to win it but I'm not going in for the argy bargy. I've had too many incidents like that over the years."

The 33-year-old will have a key part to play if United are to claw back the nine-point advantage currently held by leaders Chelsea, starting at home to Bolton on St Stephen's Day.

Even so, he does not expect to feature in all four matches over the packed festive programme and believes manager Alex Ferguson will try to spread the burden of the heavy workload.

"We do have two or three important players injured but that is where the squad comes into it," he told MUTV.

"I'm not sure I can play four games. The manager will look at the priority of getting the team right but physically I feel really good at the moment."

Keane believes that a United side unbeaten in the league for almost two months is starting to fulfil its promise and the second half of the season will provide a test for the teams above them - Chelsea, Arsenal and Everton.

"We're aware we are chasing three teams now and we can't afford any slip-ups," he said.

"I think it is an important second half of the season and if and when Chelsea slip up we are ready to pounce.

"We have bought one or two good young players and hopefully they will get stronger in the New Year.

"The foundations of the team and the club are rock solid. Where to judge it is on the football pitch and hopefully we can do that in some of the big games coming up."

Keane also praised Chelsea for the football they were playing but wondered whether being in an unfamiliar position at the top of the table would work against them as the tension increases later in the season.

"The way Chelsea are playing you have to give credit where it's due. Their team is a lot better than the ones over the last few years," he added.

"Their manager this year (Jose Mourinho) seems to be stronger mentally but only time will tell if they can handle the pressure."