Robin van Persie struck after 33 seconds as Manchester United edged past West Ham 1-0 at Old Trafford.
But it turned into a nervy evening for the Barclays Premier League leaders, who were well below their best.
And whilst the visitors were not exactly on top form either on a bitterly cold evening, they came close to snatching a point late on, when Anders Lindegaard denied Carlton Cole from close range.
Any latecomers would hav missed Van Persie's 12th goal in his 18th game for United.
The Dutchman checked inside from the left flank, then made his way to the edge of the area as Michael Carrick exchanged passes with Anderson.
Van Persie swivelled past Winston Reid as he collected Carrick's forward pass, then profited from James Collins' desperate attempt to block, which only sent the ball looping over Jussi Jaaskelainen and into the net.
West Ham are resilient, though, and skipper Kevin Nolan turned Matt Taylor's low corner into the side-netting.
At the other end Javier Hernandez screwed a shot wide and the Mexican was responsible for the only other decent chance in the opening period, when Jaaskelainen turned his shot from the edge of the area around a post.
Once again anchored in midfield, it was one of those nights when Wayne Rooney struggled on the periphery of proceedings. It was not until he took aim with a curling shot from the edge of the area that Rooney really become a central figure as Jaaskelainen tipped it round and his departure 14 minutes from time was not unexpected.
Anderson's signal to the bench that he needed to come off was not a good sign and before Phil Jones could replace him, Cole, on for Andy Carroll, came agonisingly close to levelling, but Lindegaard turned away his five-yard effort as United held on.