Latics recorded a famous FA Cup fourth-round victory as they completely outplayed Premier League West Ham at the DW Stadium.
The injury-hit Hammers posed little threat throughout as Latics ran out comfortable 2-0 winners with a brace from top scorer Will Grigg.
Grigg opened the scoring after only seven minutes when he powerfully headed Nathan Byrne’s superb cross past England keeper Joe Hart.
The Hammers misery was further compounded when Arthur Masuaku was sent off for spitting at Nick Powell just after half time.
Fomer Latics loanee Reece Burke handled the ball in the area after 62 minutes and Grigg confidently drove his penalty kick down the centre of the goal as Hart dived to his left.
The Hammers could have few complaints about the result as Latics looked more like the Premier League team and progressed into the fifth round for only the fourth time in their history.
Paul Cook made one change from the team which defeated Plymouth Argyle 3-1 last weekend, with Callum Elder replacing Reece James at left back.
Latics were at their best right from the kick off pressing high up the pitch and giving the Hammers little time on the ball.
They went ahead on seven minutes with a superb attacking move. Max Power fed Byrne out wide on the right and the wing-back produced a pinpoint cross to Grigg whose perfectly placed header found the top corner of the net.
Latics were in the ascendancy and they nearly went two up when Chey Dunkley headed home from close range, but the linesman flagged for offside.
It was one-way traffic as Powell fired just over the crossbar from the edge of the box and Jacobs tried his luck from distance but Hart saved low down to his right.
The Hammers had a rare foray forward just before half time and Latics captain Sam Morsy had to block a couple of shots before Reece Oxford blazed high over the crossbar.
West Ham started the second half with more intent, probably after a verbal blasting from David Moyes, but all his work was undone on 49 minutes when Masuaku was sent off for spitting at Powell.
Latics were in complete control now and they increased their lead on 62 minutes when Grigg scored his second from the penalty spot after Burke had handled in the area.
Powell might have added a third on 75 minutes when he nearly got on the end of Byrne’s excellent low cross but Latics still ran out comfortable 2-0 winners.
Questions have to be asked about the West Ham players’ attitudes but we should not take anything away from Latics who were absolutely magnificent from minute 1 to minute 95.