On loan from Watford, Dawson has been outstanding in the Hammers’ push for a top-four slot but settled the contest in the wrong way at the start of the second half as he turned Bruno Fernandes’ corner into his own net under pressure from Scott McTominay at the near post.
Marcus Rashford and Mason Greenwood also went close in a one-sided contest as West Ham failed to threaten until Said Benrahma’s introduction after an hour.
The result kept United in second but with the teams from fourth to seventh all failing to win this weekend, they now have a nine-point advantage over West Ham, who remain fifth, but do have a match in hand.
David Moyes’ West Ham are three points off a place in the top four. The result means Moyes remains without a win as an away manager at Old Trafford, a sequence that now extends to 11 defeats in 15 attempts in all competitions.
The win marks the first time United have done double over the Londoners since 2013-14, when Moyes took over from Sir Alex Ferguson.
West Ham never really looked capable of winning the game. The absence of Pablo Fornals through injury cost them an element of creativity they did not introduce until Benrahma came on, while Maguire and Victor Lindelof were assured on the rare occasions West Ham had a chance to create any aerial problems.
