Jack Grimmer's winner proved be the final nail in the coffin for Mark Hughes as he was sacked after Stoke were dumped out of the FA Cup by Coventry.
Defender Grimmer struck in the second half to push Hughes closer to the exit following the Sky Blues' 2-1 third-round win.
Charlie Adam had cancelled out Jordan Willis' opener but Sky Bet League Two outfit Coventry outfought and outfoxed Stoke at the Ricoh Arena.
Stoke were the first to threaten after 11 minutes when Willis hacked Mame Diouf's effort off the line. But it was a scrappy opening, not helped by the terrible pitch which had been ravaged by the ground-share with Wasps.
Stoke remained comfortable and Stephen Ireland, on his first appearance since May 2016 after a broken leg, fired just wide from 18 yards after 21 minutes. But Coventry stunned their Premier League visitors by taking the lead three minutes later.
After a quick break, Max Biamou's shot was deflected for a corner and, from the delivery, Grimmer knocked the ball across goal for Willis to head in.
The Potters were flat and struggling for inspiration and they twice survived in first-half injury-time. First, Marc McNulty wasted a golden chance when he rounded Jack Butland but rolled his shot across goal, and then the striker was denied by Butland and saw Geoff Cameron clear the ball off the line.
And McNulty was made to count the cost eight minutes after the break when the Potters levelled from the penalty spot. Ramadan Sobhi was brought down by Willis and Adam sent Liam O'Brien the wrong way to give Hughes a lifeline.
But Stoke were level for just 13 minutes as Grimmer grabbed the winner against the run of play. The right-back was given too much time to cut in from the flank and his low effort flew past an unsighted Butland.
It sent Coventry through as they survived a late rally when O'Brien denied Diouf before, with five minutes left, the striker headed wide from point-blank range.
Goalkeeper O'Brien had the final say, turning over Peter Crouch's volley to condemn Stoke to defeat - and possibly Hughes to the sack.