Sir Alex Ferguson's men shellshocked the hosts to go 11 points clear in second place despite playing comfortably within themselves at times against an injury-depleted Spurs side
An uneventful first half was dominated by a disallowed Spurs goal, Emmanuel Adebayor divisively judged to have handled prior to finishing, before Wayne Rooney headed home from a corner moments before the whistle.
Despite not being at the top of their game, United pushed clear after the interval, Ashley Young catching the eye first with a well-taken volley from a tough angle and then a delightful finish from outside the area to double his tally. Jermain Defoe later secured a late consolation having capitalised upon a loose pass from Ryan Giggs.
Neither Gareth Bale nor Rafael van der Vaart were available for the home side due to illness and injury, respectively, Sandro, Aaron Lennon and Jake Livermore coming into the midfield with Scott Parker suspended. Louis Saha, meanwhile, started against his former club.
Rooney recovered sufficiently from a throat infection to return to the visitors’ starting XI in place of Javier Hernandez, Young the other alteration from United’s defeat of Norwich, replacing Giggs.
With shots scarce, David de Gea made a key save near the 20-minute mark from Adebayor, having caused the chance himself with a poor clearance that was easily intercepted by Sandro.
The home side, starting to dominate, had the ball in the net in the 37th minute. Lennon’s enterprising run inside the area from the left wing forged a chance for Adebayor, who received the ball via Saha’s effort and bundled it into the net in a slightly scrambled manner, but referee Martin Atkinson ruled it out on grounds of the Togolese handballing as it reached him.
Despite a period on the back foot, United edged in front just before half-time through a simple goal. The Red Devils having earned a corner, Young delivered an in-swinger from the left and Rooney’s impressive off-the-ball movement coupled with the strength to hold off Kyle Walker allowed him to head home decisively for a 1-0 lead.
Spurs resumed probing after the break and came close when Livermore’s rasping shot took a thin deflection off Saha’s leg to threaten De Gea, but the Spaniard reacted sharply to get low down and block with his arm.
Yet, despite being on the back foot, United stretched their lead a minute later. Luka Modric’s lazy marking let Nani through in space on the right byeline and the Portuguese played the ball across the area. It broke to Young just past the far post who had a difficult angle but still volleyed low, evading a small crowd and creeping into the net.
Spurs looked to riposte, Lennon carving some room once again, but, receiving the ball with time to volley, Assou-Ekotto limply struck the ball utterly wayward.
White Hart Lane was in shock and it only got worse for the north Londoners as Young picked the ball up a little way outside the area. The England winger pushed inside a little to get sight of the net and struck, placing his shot with delightful precision into the top-right corner.
Harry Redknapp's side seemed to accept that matters were settled and the game drifted in the final 15 minutes, the away fans crowing loudly over the subdued home supporters.
There was, however, a late consolation. With 86 minutes gone, the United defence seemed to switch off and substitute Giggs' lax pass into nowhere allowed fellow replacement Defoe to run on and dispatch an uncomplicated finish past De Gea.
Spurs had no time for an accompanying late rally, however, and the final whistle soon confirmed the setback that left any remaining title hopes very distant indeed.