Wayne Rooney opened the scoring with 20 minutes gone but the Red Devils failed to kick-on against the Royals in a less-than-entertaining first period.
And the below-par display continued after the break, with both sides failing to threaten the other, meaning Sir Alex Ferguson’s men take full advantage of Manchester City’s loss to Everton while their manager-less opponents remain in deep trouble at the bottom.
Rooney, Robin Van Persie and Danny Welbeck all started for the hosts in an attacking line-up, while Nani (hamstring) missed the game and Alexander Buttner replaced Patrice Evra at the back.
Stuart Taylor continued in goal for the Royals, who were under the control of caretaker boss Eamonn Dolan after Brian McDermott’s sacking, while Pavel Pogrebnyak was left out despite being available after a three-match ban.
After a sluggish opening 15 minutes or so, Ashley Young collected a fine ball from Rio Ferdinand before flashing a shot narrowly wide of the post in the first half chance of the clash
And the centre-half was again heavily involved as United got the breakthrough with 20 minutes played. Ferdinand expertly carried the ball up from the back, before finding Rooney whose strike deflected off Alex Pearce and looped over Taylor.
Welbeck then dragged a shot wide, with Rooney and Van Persie sending long-range efforts into the keeper’s arms, as Ferguson’s men comfortably dominated possesion but just failed to create any clear chances against a stubborn Royals defence.
Hal-Robson Kanu went inches from an equaliser with a superb, curling left-footed effort from outside the United box, in the visitors’ first shot at goal, but the score remained 1-0 at the half-time whistle.
Reading started the second period much brighter and were unfortunate not to be awarded a penalty when Nemanja Vidic shoved Adrian Mariappa to floor in the box.
However they struggled to create any chances of note as the match became scrappy, with both sides allowing sloppiness to creep into their already lacklustre play.
The Red Devils finally sprung back into action with about an hour played as Welbeck had a strike deflected wide and Van Persie and Young saw efforts rise over the bar.
Taylor then palmed away a powerful Van Persie free-kick as the slight pressure continued, but it only lasted for a matter of minutes before the match returned to its former uninspiring standard.
Reading offered little in attack as they searched for another late goal, and it was in fact the hosts who went closest to a second through a Rooney pile-driver and a neat effort from Giggs in the last five minutes.
Van Persie then also shot acrobatically over the bar very late on before the hosts held firm to grind out another win that puts even more space between them and rivals City.