Wayne Rooney had already warmed Michel Vorm's hands with a stinging drive before Patrice Evra put the visitors ahead, arriving to glance a header in off the far post from a Robin van Persie corner.
United who felt they had been victims of an injustice as Michu levelled on the half-hour mark.
Evra was caught out by Jonathan De Guzman's clever run and when De Gea could only parry the Dutchman's angled shot, Michu was on hand to tap in.
But United offered a reminder of their quality in first-half stoppage time when Evra easily got past Nathan Dyer and intelligently pulled the ball back to Rooney, but the England forward fired directly at Vorm.
United were finally exerting some authority after the break and Van Persie came close to putting them back in front as he cleverly diverted a Rooney cross goalwards, only to see his effort cannon away off the bar.
Substitute Javier Hernandez wasted another presentable chance as he failed to control Van Persie's astute pass and Vorm gratefully held the Mexican's deflected strike.
Worse was to follow for United when Rooney dispossessed Chico Flores but allowed the defender to get back and intercept a slack pass which should have given Hernandez an easy finish, much to the fury of his manager.
Vorm tipped a Carrick header against the bar while Van Persie and Young were denied by blocks from Williams and Davies, although there was a suspicion of handball about the latter, as Swansea held out.
- Sports & Recreation
- Patrice Evra
- Wayne Rooney
- Michel Vorm
- Jonathan De Guzman