United edged a tense encounter with Fulham at Craven Cottage, picking up three points to continue to set a breathless pace at the head of the Barclays Premier League table.
A thrilling first period yielded chances aplenty for both sides, with United thrice hitting the woodwork, while David De Gea spectacularly fended away two efforts from the hosts.
A floodlight failure late in the first half sent the game limping into the interval, however, and Martin Jol's side stifled the Reds for long periods thereafter.
Both sides managed to make presentable chances without making the all-important breakthrough, until Rooney latched onto Jonny Evans' long pass and converted a clinical 79th-minute winner.
You can view a gallery of images from a vital victory by clicking on the main photo above.