Arsenal clinched a 2-1 over West Ham United to enter in to the Premier League top five as Sam Allardyce's side lost for the first time at home since August.
Cameroonian midfielder Alex Song had a 20-yard volley ruled out for offside for the hosts, denying them a chance to hold Arsenal to a draw.
Santi Cazorla put the visitors ahead from the penalty spot, following a foul by Winston Reid, before Danny Welbeck doubled Arsenal's lead in front, the BBC reported.
Cheikhou Kouyate's header gave the hosts hope but West Ham were unable to avoid a second successive defeat.
It was Arsenal's ninth win in a row in all competitions against West Ham as they moved level on points with fourth-placed Southampton and just three points behind third placed Manchester United.
Allardyce, who opted to rest key players Song and Diafra Sakho for the 2-0 defeat at Chelsea on Boxing Day, disagreed strongly with the decision to disallow Song's goal, claiming Sakho was not in the goalkeeper's eyeline when he was adjudged to be offside.
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West Ham had won six of their last seven league home games but, despite heavy late second-half pressure, lacked the quality needed for the leveler.
Former Arsenal man Song, on loan from Barcelona, almost made an instant impact with a low volley into the bottom corner of the net from 20 yards early on. Sakho was penalised for standing in an offside position in front of goal, though, despite not touching the ball.
Arsenal manager Arsene Wenger said that they had a committed and united performance, claiming that the keeper made some good saves. He added that they knew they needed to be good in the air.
Wenger further said that he didn't know why Song's goal didn't stand, adding that he thought it would. He said that they scored a good second goal and had many opportunities to score another.
Wenger claimed that his side did dig deep, adding that it is down to consistency and they are slowly getting there.