Wayne Rooney showed he is back to full fitness with the opening goal that was cancelled out just after the half-hour by Roque Santa Cruz, but Cristiano Ronaldo's powerful free-kick ensured that United go into Tuesday's titanic Champions League encounter with Inter Milan on a run of 16 wins from their last 17 matches.
On the downside, with Nemanja Vidic already ruled out against the Italians through suspension, they may also be without Jonny Evans after the centre-back limped out after an hour.
The consistent form of Ryan Giggs and Paul Scholes is the only reason they are still involved under Sir Alex Ferguson and the United manager showed a distinct lack of sentiment when he denied Edwin van der Sar the chance to set a European record for time without conceding, which a clean sheet after 89 minutes last night would have given him.
The Dutchman was left out of the squad with Ferguson clearly having an eye on Inter and the veteran will now be looking to claim a personal record after the shaky Tomasz Kuszczak conceded after 31 minutes at Old Trafford, the first Premier League goal scored against United in 1,333 minutes since their 2-1 defeat at Arsenal on Nov 8.
Before that, after what has seemed like months of just about getting by, United finally started to show the swagger that was their trademark last season. They were able to pull Blackburn's five-man midfield and Dimitar Berbatov was finding plenty of room in deep positions despite Vince Grella being deployed just in front of the visitors' back four.
Rooney, who made his first start since suffering a hamstring problem in the 1-0 win over Wigan on Jan 14, showed he is now fully recovered from the problem when he stole the ball from David Dunn on halfway before slipping through a delicate pass for Michael Carrick that was just cut out by Gael Givet.
Ronaldo was allowed to play in a teasing cross from the right that just evaded Rooney and Carrick before it was cleared by Ryan Nelsen before Patrice Evra's follow-up flew just wide.
Midway through the opening period, United got their breakthrough when Rafael da Silva slipped the ball to Nani down the right flank and the Portuguese midfielder's cross had just enough power on it to beat Nelsen before Rooney touched in from six yards out.
But just after the half-hour, United's long spell without conceding came to an end. Andre Ooijer shrugged off Nani to win the ball on halfway and the Dutch defender's pass was weighted perfectly to put Santa Cruz in behind the United defence.
The Paraguayan held off Ferdinand, who collided with Kuszczak and Santa Cruz touched into an empty net from a narrow angle.
Evans had a header ruled out for pushing in first-half added time and after the restart, Ronaldo drove narrowly wide after he cut inside past Warnock as United's frustration began to build. That was again in evidence when Ronaldo was booked for diving after he went down under imagined contact from Givet.
After Pedersen's effort was deflected wide, the ball was lobbed back in by David Dunn from the resulting corner and headed on by Keith Andrews. Nelsen stabbed against the post before El-Hadji Diouf's follow-up was held by Kuszczak.
It was not easy to remember when Ronaldo last scored a thumping free-kick but he managed one just before the hour to retain his trademark. After Andrews had fouled Evra on the United left, the Portuguese rifled the ball across goal into the top corner of Robinson's goal for his 16th of the season.
Rafael was fortunate not to concede a penalty for a challenge on Pedersen but United's form remains imperious.