Hull took the lead against the run of play in added time at the end of the first half after Leicester had missed plenty of chances. Kasper Schmeichel saved excellently from Curtis Davies' header before the rebound was acrobatically kicked in by a combination of Abel Hernandez and Adama Diomande although it was officially awarded to Norwegian striker Diomande.
The lead was short-lived though, with Riyad Mahrez levelling things from the penalty spot after Demarai Gray was adjudged to have been fouled by Tom Huddlestone on the edge of the area just 14 seconds into the second-half.
Hull then got their noses back in front on 57 minutes with a powerful left-footed strike from Robert Snodgrass after sloppy defending from Leicester and the Tigers held on to record a major upset.
Manchester City got off to a winning start to the Pep Guardiola era with a late 2-1 victory against Sunderland.