Robin van Persie's 27th-minute strike deflected off Phil Bardsley and Titus Bramble for the only goal of the game, making United the only team to win 25 of the first 30 games of a top flight season in England.
A mixed display from the Reds might have yielded more in a one-sided first period, but the relegation-threatened hosts improved markedly after the interval to keep United on the back foot for long periods.
Mindful of Monday’s looming FA Cup quarter-final replay at Chelsea, Sir Alex Ferguson made good his pre-match suggestion that he would chop and change his squad to absorb the rigours of a congested calendar.
Wayne Rooney, Rio Ferdinand, Ryan Giggs and Chicharito were omitted completely from the 18-man party, while Patrice Evra savoured the rare experience of starting the game on the bench.
That meant a second successive start for Alexander Büttner, with the Dutchman on the left side of a defence also comprising Rafael, Chris Smalling and Nemanja Vidic ahead of goalkeeper David De Gea. Michael Carrick partnered Anderson in central midfield, flanked by Antonio Valencia and Ashley Young, while Shinji Kagawa provided deep-lying support to van Persie in attack.
The Dutchman, looking to curtail a comparatively barren run of form in front of goal, had the game’s first attempt on goal as his long-range header from a Rafael cross drifted comfortably to Simon Mignolet.