London - Cracks finally appeared in Manchester United's defensive armour on Saturday although the champions still rolled on towards the Premier League title with a 2-1 home victory over struggling Blackburn Rovers.

Roque Santa Cruz's first-half equaliser for Blackburn after Wayne Rooney had put United ahead ended a record run of 14 consecutive clean sheets in the league before Cristiano Ronaldo's firecracker free kick sealed victory after the break.

United's 10th consecutive league win, achieved despite a ragged performance, moved them to 62 points, eight ahead of second-placed Liverpool who face Manchester City on Sunday.

United manager Alex Ferguson admitted his jittery side had been given a wake-up call by Rovers who were unlucky not to get a point after hitting the post and having a strong penalty claim turned down.

"We just deserved it, no more than just," Ferguson told Setanta Sport. "We gave away a bad goal and that was not indicative of our performances recently.

"They made it a real fight for us. This was a great lesson today, it just shows what this league is like."

United badly missed Edwin van der Sar in goal and Nemanja Vidic at the heart of their defence, both of whom were rested.

Rooney struck early with a close-range finish but Rovers stunned the Old Trafford crowd when Santa Cruz nudged the ball past keeper Tomasz Kuszczak and rolled it into the net from a tight angle.

United defender Jonny Evans had a headed goal unluckily disallowed by referee Howard Webb just before halftime while Rovers' Ryan Nelsen stabbed a shot against the post shortly after the interval.

United were not themselves, but Ronaldo can usually be relied upon to provide some inspiration and he did it again on the hour when he whipped a fierce free kick past the flailing arms of Rovers keeper Paul Robinson.

Rovers manager Sam Allardyce was annoyed that Ronaldo had escaped a possible sending off for a kick at David Dunn moments earlier and enraged when his side were denied a late penalty after Morten Gamst Pedersen was pulled back by United's young right back Rafael.