Former Crystal Palace teenager Victor Moses netted his first Premier League goal in the 30th minute to put the Latics ahead but Ian Dowie's troops hit back and Will Atkinson's equaliser three minutes before the break sparked an all too rare comeback for the visitors.
Mark Cullen - on his first start for Hull - grabbed his first goal for the club in the 64th minute but Gohouri had other ideas, popping up in the dying seconds to relegate the Tigers.
Hull sat three points behind West Ham - who lost 3-2 to Fulham on Sunday - before kick-off and needed a win to put off relegation until the last weekend of the season.
Both sides traded chances in the opening exchanges with Steven Mouyokolo bundling Hugo Rodallega's effort for Wigan behind and Atkinson testing Latics keeper Vladimir Stojkovic.
Hull midfielder Kevin Kilbane then fired a left-foot shot just wide before 19-year-old Moses opened his Wigan account on only his second start for the club.
The winger left Bernard Mendy for dead before cutting inside Mouyokolo and slotting his shot past Matt Duke via the post.
Moses should have netted his second moments later and put the result beyond doubt but he kicked thin air when unmarked in the box and Hull soon took full advantage.
Atkinson headed home Kilbane's pin-point cross in the 42nd minute but it nearly wasn't allowed as the linesman initially flagged for offside before swiftly changing his mind.
Wigan piled on the pressure after the break but it was Hull who found the net and took the lead against the run of play in the 64th minute.
George Boateng sent over a cross that Stojkovic failed to collect, Gohouri missed and Cullen - at the far post - powered home with his head.
However, deep into stoppage time Ivorian Gohouri made amends, acrobatically turning in substitute Paul Scharner's cross to grab an unlikely draw for the Latics.