First-half goals from Richie Smallwood and Ryan Longman saw lowly Hull win at Coventry to dent the Sky Blues' play-off hopes.
The home side began the night five points outside the top six, but fell 2-0 behind inside the opening half-hour.
Smallwood gave Hull a fourth-minute lead before a thumping finish from Longman doubled the advantage.
Ian Maatsen thought he had pulled one back late on, but officials did not receive confirmation that the ball had crossed the line.
His half-volley was partially cleared off the line by Jacob Greaves and cannoned into goalkeeper Matt Ingram and seemingly over the line, but goalline technology did not send its signal to referee John Busby.