Swansea City were made to rue a series of missed first-half chances as David Meyler's goal sent a Hull City side boosted by Jake Livermore's return into round four of the League Cup on Tuesday.
Livermore was named in a much-changed Hull line-up, his first action since being cleared to play following a positive test for cocaine, and managed to get through 69 minutes before he was substituted to a standing ovation at the KC Stadium.
Garry Monk's men beat Hull twice when this game was a Premier League fixture last season and Eder, Wayne Routledge and Angel Rangel all wasted great chances for the Welsh club.
And Hull made the most of Swansea's profligacy as Meyler tapped in after Shaun Maloney's header was saved.
Swansea pressed to get back into the game and Routledge had a goal chalked off shortly after the break, but the 2013 League Cup winners saw their participation ended for another season.
The hosts were under pressure early but Eder could only skew a six-yard effort from Franck Tabanou's excellent whipped centre over the crossbar.
Hull were off the hook again as Eldin Jakupovic's attempted clearance was charged down by Eder and rebounded off the post. The forward recovered the ball and played in Gylfi Sigurdsson, but his shot was brilliantly charged down by Curtis Davies.
Swansea remained in the ascendency and Jakupovic made amends with a fine point-blank save from Rangel's header.
And Hull made Swansea pay four minutes before the break. Maloney's powerful header was parried by Kristoffer Nordfeldt and Meyler tapped home with the ball seemingly going in anyway.
The visitors thought they had found a way back into it after the break when Routledge slotted home after collecting Matt Grimes' throughball, but the linesman had already raised his flag.
Swansea continued to see plenty of the ball but the chances began to dry up as the half wore on and Hull easily saw out the win.