Chelsea hold key to title - Sir Alex

Sir Alex Ferguson is increasingly wary of the threat posed by Chelsea to Manchester United's defence of their Barclays Premier League title.

United have a five-point lead at the top, but Ferguson has noted the second-placed Blues' stealthy progress under Avram Grant.

The Red Devils are set to travel to Stamford Bridge at the end of next month and Ferguson told his club's official website, www.manutd.com: "I think Chelsea hold the key - especially because we go to their place, where they've got a formidable record."

He added: "We've established a good lead but we're not taking anything for granted - we have to carry on playing the way we have been.

"I've said all along, the team who shows real consistency between now and the end of the season will win the league."

United's 3-0 win at home to Liverpool last weekend has given them added momentum for the run-in.

"We've developed this season, and I think you saw that maturity reach its peak in our win over Liverpool," said Ferguson.

"We've retained last season's consistency; we're challenging for the league - and we're in the quarter-finals of Europe."