The Mexican star struck early against the Premier League new boys to give Sir Alex's Ferguson's men the spoils in a hard-fought encounter
Javier Hernandez’s 11th minute strike gave the visitors all three points, with the Mexican slotting home after Ryan Giggs played him clean through after Rangel’s defensive error.
Swansea started in brave fashion in front of their home fans, opting for a 4-3-3 formation against the reigning champions, who welcomed Michael Carrick and Ryan Giggs back to the starting line-up.
It was a tense 90-minutes in Wales, with both sides carving out a host of chances, with Scott Sinclair guilty of the worst miss of the match when he allowed a cut-back to slip through his legs with the goal gaping before him.
In the end, the tie was settled by Hernandez's early strike, with the Mexican showing just how crucial his clinical finishing could be to United's title chances this season.
The win keeps the Red Devils on the tailcoats of fierce rivals Manchester City, who cemented their place at the top of the pile with a 3-1 win over Newcastle United earlier on Saturday.