Carlos Tevez spared Manchester United – virtually at full strength despite the proximity of their Champions League trip to Barcelona – from defeat with a close-range header with just two minutes of normal time left. Blackburn had taken the lead after 21 minutes when Roque Santa Cruz sidefooted the ball past stand-in goalkeeper Tomasz Kuszczak.

If Sir Alex Ferguson had one eye on next Wednesday's Champions League date in the Nou Camp, it was not apparent from his team selection. With one exception – Kuszczak deputised for Edwin ven der Sar – United were at full strength, with Nemanja Vidic, fit again, restored alongside Rio Ferdinand in central defence and Ryan Giggs and Tevez recalled to reinforce the attack.

Blackburn drafted in Jason Roberts up front as the target for David Bentley to supply with that much-admired range of passing. Two years ago, Bentley announced himself as a Rovers player by scoring a hat-trick against United in a 4-3 win. The match ball from that occasion is on show in a display case in his front room, and he reran the DVD in midweek.

“It’s a memory I treasure,” he said, “but I prefer to look forward rather than back. I’m looking to perform on a consistent, rather than one-off basis.” With the international friendlies against the United States and Trinidad and Tobago coming up, it was the ideal opportunity to impress for the clever midfielder who aims to replace David Beckham on England’s right.

On this occasion, Mark Hughes deployed him just off the main striker, Roberts. United also used a solitary front man, Wayne Rooney, but he was supported by an attacking row of three just behind.

Santa Cruz started on the right side of Blackburn’s midfield, but joined Roberts at every opportunity, and the two of them combined in a raid that might have produced a penalty after five minutes. The Paraguayan’s shot was deflected to Roberts, who nicked the ball past Kuszczak and was impeded by the keeper as he moved in for the kill.

Reprieved, United countered quickly and Rooney’s cross from the byline on the right found Tevez, whose shot was blocked by Christopher Samba with Brad Friedel scrambling.

It was Rovers, however, who struck first. A long throw from the left, hurled into the penalty area by Pedersen, evaded Ferdinand and then hit him via Vidic’s maladroit touch before ricocheting to Santa Cruz who, from near the penalty spot, drove past Kuszczak’s left hand and into the corner of the net.

United responded with a 25-yard free kick from Cristiano Ronaldo, but it lacked the accuracy to inconvenience Friedel, and Blackburn threatened to double their lead after half an hour, when Bentley’s siege-gun shot from long range had Kuszczak reaching urgently to tip the ball over. Events were not following the script from the United viewpoint. It must have made good TV viewing for Chelsea and their supporters.

Like Blackburn before them, United thought they should have had a penalty after 37 minutes, when Andy Reid’s challenge floored Rooney near the byline on the left. As in Roberts’s case, the claim looked valid, and Rooney was still seething at the injustice when he hacked down Samba and was booked shortly afterwards.

United would have had equality just before the interval but for a reflex save by Friedel who, flying to his left, beat out the thumping header with which Ronaldo met Giggs’s corner from the right. It was Ronaldo’s only contribution of note in a first half that ended with him belting a free kick straight at Friedel.

Giggs, like Ronaldo, had been anonymous throughout the first 45 minutes, and was replaced by Nani on the resumption. It got no better for Portugal’s finest, who blasted his next free kick into the defensive wall and was then flattened by Pedersen, who somehow escaped the booking the cynical foul warranted.

Ferguson moved to the edge of his technical area to issue fresh instructions. The old boy was worried, and with every reason. Blackburn were competing for every ball as if they, and not Chelsea, were hot on the league leaders’ heels.

Nani fired wildly over when well placed after a pacy break through the middle by Ronaldo, who was stirring himself at last. He was desperately close to supplying the equaliser after 65 minutes when a misplaced defensive header by Reid allowed him to get in a firmly-struck drive from the left that Friedel touched on to his left-hand upright.

Back came Blackburn, Santa Cruz heading on to the roof of the net after Warnock's long free-kick had looped over Evra. Blackburn were excellent, but it was a poor performance by United, with Rooney frustration personified and threatening to boil over at any moment.

Rovers might have had a second goal to put the issue beyond doubt, but when Pedersen profited from a mistake by Vidic and fired in alow cross from the left, the ball narrowly evaded Ryan Nelsen, coming it at pace at the far post.

As United laid siege to the Blackburn goal there were a series of fine saves from Friedel.

Blackburn Rovers: Friedel, Reid, Samba, Nelsen, Warnock, Santa Cruz, Emerton, Vogel (Mokoena 85min), Pedersen, Bentley, Roberts

Manchester United: Kuszczak, Brown (O’Shea 81min), Vidic, Ferdinand, Evra, Carrick, Scholes, Ronaldo, Tevez, Giggs (Nani ht), Rooney (Park 90min)

Scorers: Blackburn: Santa Cruz 21 Manchester Utd: Tevez 88
Yellow cards: Blackburn: Reid Manchester Utd: Rooney
Referee: R Styles
Attendance: 30,316