Roberto Martinez's side overcame Sam Allardyce's men in an entertaining encounter, with the hosts looking comfortable despite the threat of a late comeback from the Hammers
The victory was just reward for a strong display from Roberto Martinez's side, which slick movements and passing was too much for the visitors, with Jean Beausejour, Shaun Maloney and Arouna Kone tormenting the Hammers defense throughout.
The 4,000 traveling fans were left with more questions than answers as a lack of an alternate option in the wake of Ricardo Vaz Te's injury left them looking predictable.
Martinez started Franco Di Santo up on his own, with support coming from Beausejour on the left, while Andy Carroll and Kevin Noble started for the away side, with boss Sam Allardyce looking for his side to go on the offensive from the off.
Both sides started brightly, with the Hammers looking to hassle the Latics defense as early as the first minute. Andy Carroll heading an early chance over, and slammed a free kick into the wall minutes later.
While the early warning signs came from the visitors, it was Wigan which struck first, and in spectacular fashion. Beausejour won a corner in the eighth minute, and swung the ball into an unmarked Ramis, who blasted in a left-footed volley from 18 yards out. Jaaskelained was furious his defenders nowhere to be found.
Ramis then earned a booking by taking out Diame in the 18th minute, and Wigan was lucky Mark Noble wasted the 25-yard free kick.
Maloney struck a swerving effort from 30 yards that Jaaskelainen did well to parry away from danger after 20 minutes, with the Hammers defense slow to acknowledge the danger again.
West Ham created few chances after a frenetic opening, but James Collins almost turned in an effort on 36 minutes following a Noble free kick, yet the ball dribbled into Al-Habsi's hands.
During a frantic five-minute period Kone and Di Santo wasted three opportunities between them, and Carroll almost found an equalizer in injury time after heading wide from Noble's delivery.
Benayoun was replaced at the interval by Modibo Maiga, but James McArthur gave the home side a two-goal advantage two minutes into the restart. Jaaskelainen shanked a clearance to concede possession, and the ball was worked in from the left, McArthur slammed home a half volley as the Hammers again failed to pick up their men.
Wigan nullified Carroll's threat by picking up the midfield runners behind him, leaving the forward isolated. Carroll had a golden opportunity on the hour mark but couldn't control a fine cross, with the ball running away harmlessly.
Tomkins hit the bar late on for the visitors with a deflected volley and scored a fine header in the 92nd minute, but it was too little, too late.
The win leaves Wigan with eight points from nine games, and four clear of the relegation zone. West Ham slip to ninth place, but will have to be better to avoid being sucked further down the table.