Manchester United "have been woeful for the past 18-months", according to Alan Hansen, but concedes it is a measure of their durability and Premier League knowhow that they remain a potent force and worth title contender.

Manchester United's victory over Arsenal ensured Sir Alex Ferguson's side maintained their impressive defence of their title and challenge with Manchester City, yet Hansen believes United continue to look below their vintage best.

Despite winning last season's Premier League title, Hansen intimates Manchester United are not the force of old and instead believes they are benefiting from their years of experience in winning the Premier League title.

The Match of the Day pundit believes Sir Alex Ferguson's side know how to last the distance in a league title campaign and because of that, Manchester United are the only club that can prevent Manchester City from winning the Premier League title.

"By their own standards, (Manchester) United have been woeful for the past 18 months. I can't recall Sir Alex Ferguson's team being so bad for two successive seasons." Hansen told The Daily Telegraph.

"At times, they have been at the bottom of the scale, but United are United and they are still just three points off the top, having been so unimpressive at times this season."

Hansen suggests Manchester United are sure to improve on their squad in the summer following something of a transitional period, and therefore the rest of the division must follow suit or risk being left behind by the two Manchester clubs.

"Despite being so bad, their experience of winning has seen United win the title last season and reach another Champions League final, so they can never be overlooked." He added. "I cannot see any way that they will not improve next season, so that is the challenge that Spurs face."

Manchester United are three points behind Manchester City and five ahead of third placed Tottenham in the Premier League. The two Manchester clubs play each other in the Premier League in a potentially decisive match at the Etihad Stadium on 28 April.