Wayne Rooney's 16th goal of the season was enough to propel Manchester United 15 points clear with just nine games remaining in the Barclays Premier League title race following a 1-0 victory over Reading.
Rooney's deflected first-half effort saw off a dogged Reading outfit, who worked hard but lacked the class to fashion an equaliser.
The Royals now look certainties for relegation, sliding seven points adrift of safety with one game fewer than United to save themselves, while 13 points will do it for Sir Alex Ferguson's men to clinch a record 20th championship.
The impressive Rio Ferdinand created United's first chance with an elegant crossfield pass to Ashley Young, which the winger controlled before drilling a cross-shot just beyond Robin van Persie and the far post.
Ferdinand's next incursion was the crucial one. Nipping in to intercept Garath McCleary's poor pass, Ferdinand advanced into the open space and nipped round Mikele Leigertwood before feeding Rooney just to his left.
The striker took aim and once his shot flicked off Alex Pearce, former Manchester City goalkeeper Stuart Taylor had no chance of keeping it out.
Either side of Rooney's goal, Danny Welbeck went close on a couple of occasions and Van Persie missed from 20 yards. Only once did the visitors truly threaten before the break, when Hal Robson-Kanu let fly with a shot David de Gea would not have reached if it had been on target.
They should have had a chance to equalise immediately after it though when Nemanja Vidic shoved Adrian Mariappa over inside the box. Reading appealed for what TV replays showed to be a clear foul but referee Lee Mason was unmoved.
United failed to profit from their good fortune, with Welbeck and Young going close either side of a wild effort from Van Persie that flew out from a throw-in.
Taylor also repelled a well-struck free-kick to keep the former Arsenal man out. A Reading equaliser did not come, though.