Robert Koren scored to give Nick Barmby the perfect start to his reign as Hull's full-time manager as his side beat Peterborough to go fifth.
Posh started strongly, with Emile Sinclair and Lee Tomlin going close.
Koren had chances before he picked up Aaron McLean's cross and fired in low past Joe Lewis.
The visitors were unlucky not to be awarded a penalty when goalkeeper Vito Mannone appeared to bring down Daniel Kearns, but the Tigers held on.
Substitute Joe Dudgeon could then have made it safe but was off target on the hour.
Lewis also made fine saves to deny Robbie Brady and McLean, before Peterborough's Paul Taylor spurned a late chance to snatch a point in added time.
Defeat means Darren Ferguson's side have not won in four games.
Hull City manager Nicky Barmby:
"We rode our luck in the first half hour and maybe they should have had a penalty.
"If it had happened to us we would have been disappointed not to get a penalty. But we have had a few penalty shouts go against us recently, so maybe it evened itself out.
"Then in the second half I thought the shape of the team was a lot better. All credit to the lads as they worked it out what they should be doing and we showed what we can do. We could have scored a lot more goals than we did."
Peterborough United manager Darren Ferguson:
"The penalty incident is such a bad decision. When we asked the referee at half-time why he didn't give it, he said that the goalkeeper made an attempt to win the ball but didn't win it. So he was basically saying it was a penalty.
"The boy (Kearns) has got a six-inch gash in his leg. But what can you do? However, we were excellent and that is the best we have played for a while. We should have got a result.
"Emile (Sinclair) had two great chances early on and did everything right. He was just unlucky. We were far more fluid in the first half, but we didn't test their goalkeeper enough in the second half.
"I'm happy with the performance as a whole though and there are a lot of positives to take from the game."
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Live Text Commentary
Full Time The referee ends the match.90:00 +2:48
George Boyd takes a shot. Save made by Vito Mannone.90:00 +2:33
George Boyd fouled by Paul McKenna, the ref awards a free kick. George Boyd takes the free kick.90:00 +0:29
Paul Taylor takes a shot. Jack Hobbs gets a block in.90:00 +0:04
Free kick taken by George Boyd.90:00 +0:04 Booking
Booking Tom Cairney is cautioned.89:57
Tom Cairney gives away a free kick for an unfair challenge on George Boyd.87:51
Lee Tomlin concedes a free kick for a foul on Liam Rosenior. Vito Mannone takes the direct free kick.86:55
Robbie Brady gives away a free kick for an unfair challenge on Nick Ajose. Direct free kick taken by Joe Lewis.86:30
Aaron Mclean takes a shot. Joe Lewis makes a save.84:17 Substitution
Substitution Nick Ajose joins the action as a substitute, replacing Emile Sinclair.80:44 Substitution
Substitution Tom Cairney joins the action as a substitute, replacing Cameron Stewart.80:33
Robbie Brady has an effort at goal from just outside the box which goes wide of the right-hand upright.80:13
Unfair challenge on Liam Rosenior by Lee Tomlin results in a free kick. Liam Rosenior takes the direct free kick.79:59
Effort from just outside the box by Robbie Brady strikes the post.79:21
Cameron Stewart takes a shot. Save made by Joe Lewis.76:26
The ball is delivered by Emile Sinclair, Jack Hobbs manages to make a clearance.75:31
Cameron Stewart sends in a cross, Ryan Bennett manages to make a clearance.73:47
Shot by Corry Evans from just outside the area goes over the net.72:15 Substitution
Substitution Scott Wootton is brought on as a substitute for Daniel Kearns.
Inswinging corner taken left-footed by Robbie Brady, Headed effort from inside the area by James Chester misses to the left of the goal.71:25
Cameron Stewart crosses the ball, Aaron Mclean takes a shot. Blocked by Gabriel Zakuani.69:22
Effort on goal by Cameron Stewart from just inside the box goes harmlessly over the target.67:23
Joe Lewis restarts play with the free kick.67:23 Booking
Booking Corry Evans goes into the referee's book for unsporting behaviour.66:51
Unfair challenge on Joe Lewis by Corry Evans results in a free kick.65:51
A cross is delivered by Robbie Brady, Effort from close range by Joe Dudgeon goes wide left of the target.64:49
The ball is delivered by Joe Dudgeon, Aaron Mclean has an effort at goal from the edge of the box that misses to the right of the target.63:14
Paul Taylor concedes a free kick for a foul on Corry Evans. Jack Hobbs restarts play with the free kick.62:18 Substitution
Substitution Joe Dudgeon joins the action as a substitute, replacing Robert Koren.62:03 Substitution
Substitution Robbie Brady joins the action as a substitute, replacing Matt Fryatt.61:54
Cameron Stewart takes a shot from just inside the penalty box which clears the crossbar.61:36
Cameron Stewart decides to take the corner short.61:21
Matt Fryatt takes a shot. Blocked by Ryan Bennett.59:32
A cross is delivered by Robert Koren, clearance made by Gabriel Zakuani.57:08
Foul by Paul McKenna on George Boyd, free kick awarded. Ryan Tunnicliffe takes the free kick.55:58
George Boyd has an effort at goal from outside the penalty box missing to the wide right of the goal.54:56
Lee Tomlin takes the direct free kick.54:56 Substitution
Substitution Paul Taylor comes on in place of Joe Newell.54:56
Corry Evans gives away a free kick for an unfair challenge on Lee Tomlin.54:15
Unfair challenge on Lee Tomlin by Aaron Mclean results in a free kick. Lee Tomlin restarts play with the free kick.53:13
The ball is crossed by Robert Koren.52:52
Unfair challenge on George Boyd by Robert Koren results in a free kick. George Boyd takes the free kick.48:59
Lee Tomlin takes a shot. Vito Mannone makes a save.47:41
Joe Newell fouled by Paul McKenna, the ref awards a free kick. Free kick taken by Ryan Tunnicliffe.45:01
The referee gets the second half started.45:00 +1:03 Half time
Half Time It is the end of the first-half.45:00 +0:21
Liam Rosenior sends in a cross, clearance made by Mark Little.43:36
Robert Koren is ruled offside. Joe Lewis takes the free kick.43:23
Paul McKenna takes a shot. Save made by Joe Lewis.36:38
The ball is delivered by Andy Dawson, Liam Rosenior has an effort at goal from just inside the box that misses to the right of the target.34:00
Mark Little gives away a free kick for an unfair challenge on Matt Fryatt. Free kick taken by Andy Dawson.32:44
Robert Koren takes the outswinging corner, Emile Sinclair makes a clearance.32:37
Aaron Mclean produces a cross, Craig Alcock gets a block in.31:09
Liam Rosenior delivers the ball, clearance made by Mark Little.29:59
The referee blows for offside against Lee Tomlin. Vito Mannone takes the free kick.29:26
Foul by Paul McKenna on Daniel Kearns, free kick awarded. Free kick taken by Ryan Tunnicliffe.28:34
Andy Dawson fouled by George Boyd, the ref awards a free kick. Vito Mannone takes the free kick.26:55
Aaron Mclean provided the assist for the goal.26:55 Goal scored
Goal! - Robert Koren - Hull 1 - 0 Peterboro Robert Koren scores a goal from just outside the penalty box to the bottom left corner of the goal. Hull 1-0 Peterborough.24:52
Lee Tomlin takes a shot.23:33
Free kick awarded for a foul by Liam Rosenior on Lee Tomlin. Lee Tomlin takes the direct free kick.22:27
The referee blows for offside. Joe Lewis restarts play with the free kick.21:48
Free kick awarded for a foul by Joe Newell on Paul McKenna. Free kick crossed left-footed by Andy Dawson.18:55
Robert Koren takes a shot. Blocked by Gabriel Zakuani.17:43
Outswinging corner taken right-footed by Daniel Kearns from the right by-line, Aaron Mclean makes a clearance.16:51
Ryan Bennett challenges Matt Fryatt unfairly and gives away a free kick. Free kick crossed right-footed by Robert Koren, clearance made by Gabriel Zakuani.16:20
The ball is swung over by Cameron Stewart, Ryan Tunnicliffe manages to make a clearance.16:01
Andy Dawson produces a cross, clearance made by Ryan Tunnicliffe.14:12
The ball is sent over by Corry Evans, Header by Robert Koren from deep inside the penalty area misses to the left of the target.11:27
Shot from just outside the penalty box by Cameron Stewart misses to the left of the target.9:19
Unfair challenge on Paul McKenna by Daniel Kearns results in a free kick. Paul McKenna restarts play with the free kick.8:54
Matt Fryatt is flagged offside by the assistant referee. Gabriel Zakuani takes the free kick.7:00
Joe Newell takes a shot from just inside the penalty box which clears the crossbar.6:09
Shot from just outside the box by Lee Tomlin misses to the left of the target.5:11
The ball is swung over by Liam Rosenior, Gabriel Zakuani makes a clearance.4:34
Emile Sinclair is caught offside. Jack Hobbs takes the indirect free kick.3:48
Outswinging corner taken right-footed by Daniel Kearns from the right by-line, save made by Vito Mannone.3:30
Emile Sinclair takes a shot. Clearance made by James Chester.2:16
Corner taken right-footed by Daniel Kearns to the near post, Robert Koren manages to make a clearance.1:58
Emile Sinclair takes a shot. Save by Vito Mannone.0:54
Corner taken right-footed by Daniel Kearns to the near post, Liam Rosenior makes a clearance.0:11
Aaron Mclean crosses the ball.0:00
The game begins.
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