Darron Gibson fired the league champions into the lead midway through the first half, but with Newcastle failing to pick up anything against Aston Villa it was Hull who were celebrating come the final whistle.
Hull had a chance to take the lead early on as Sam Ricketts found Craig Fagan in space with a clever ball over the top of the United defence, but keeper Tomasz Kuszczak was alert enough to race out of his goal and smother the danger.
Richard Garcia then tried his luck for the home side, but the Australian international saw his right-footed shot from 20 yards curl well over the visitors' crossbar.
United took the lead on 24 minutes as Federico Macheda found Gibson with time outside the Hull box, allowing the Irish midfielder to pick his spot and fire in a blistering right-foot effort into the top corner of the net from 25 yards.
Danny Welbeck then came within inches of doubling United's lead as the young forward was allowed space to run at the Hull defence, but his shot from 18 yards flashed just wide of the post.
Macheda was next to come close for the visitors as the Italian's clever footwork allowed him space inside the Hull box, but his first-time shot from close range failed to hit the target.
Andy Dawson came close for the home side towards the end of the half as he found the space to hit an arrowed first-time effort from 20 yards, but keeper Kuazczak did well to tip the ball over the bar.
Nicky Barmby had a chance for the Tigers on the stroke of half-time, but the ex-Liverpool man failed to get enough power on his shot from 12 yards, allowing Kuszczak to make an easy save.
Hull had a chance minutes into the second half as a Dean Marney corner found the head of Michael Turner, but the defender's close-range header was easily saved by Kuszczak.
Substitute Richard Eckersley came close for the visitors 15 minutes from the end, but the midfielder's shot from the edge of the box whistled just past Boaz Myhill's right-hand post.
Turner then came close again from a header for City, but this time his looping effort from six yards was well held by Kuszczak.
Nani fired in shot late on for United, but his left-footed effort from 18 yards was well parried away by Myhill.