Jack Grimmer's second-half strike has fired the Sky Blues into the fourth round as they dump Premier League Stoke City out of the Emirates FA Cup.
Jordan Willis gave City the lead midway through the second half after climbing highest to head home Tom Davies' flick-on.
Charlie Adam did draw Stoke level just after halftime as the Potters brought regulars Peter Crouch and Xherdan Shaqiri into the frame, but Grimmer's 25-yard strike handed Mark Robins' side the win and progression into the final 32 of the Emirates FA Cup.
The visitors threatened to open the scoring inside the first ten minutes. Ramadan Sobhi chipped the ball over the Sky Blues defence for Saido Berahino to fire towards goal but Willis was able to hook it off the line.
Jordan Maguire-Drew was making his Coventry City debut and impressed fans in the early stages, skipping past Geoff Cameron to play a low cross towards Max Biamou in the area but Kurt Zouma was able to clear.
Stephen Ireland had not made an appearance for the Potters in over 18 months after fracturing his leg but came close to marking his return with a goal after 20 minutes. Mame Biram-Diouff brought the ball down in the area and cushioned the ball for Ireland to fire just wide.
Surprisingly, the game was nicely poised, but it would be the Sky Blues who would take the lead midway through the first half. Biamou did well to win City a corner that new-boy Maguire-Drew would drop into the area. Former Pompey defender Tom Davies gently nodded across the six-yard box for Willis to head home at the far post. The Ricoh erupted. Coventry led Premier League Stoke.
Despite the 52 league places between the two sides, the Sky Blues were now dominating and missed two golden chances to double their lead before halftime as Marc McNulty found himself twice on the end of a Biamou pass to come face to face with England number one, Jack Butland. First, he rounded the 24-year-old but found himself at too tight an angle to turn the ball home. Next, he took the effort on first-time but dragged it wide of the target. Mark Robins' side could and should have been two goals to the good.
The introduction of Peter Crouch after the break for the visitors gave them an obvious aerial threat, but some nice play down the left drew a foul from Willis in the area giving Charlie Adam the chance to draw his side level from the spot. Which he did.
The script said that City should now fold and concede defeat, but Grimmer had other ideas when he twisted into space on the corner of the area and unleashed a thunderbolt inside Butland's near post. The noise for Willis' opener was loud, but the celebrations for this one were even louder.
Stoke were now getting desperate. Shaqiri was introduced as the Potters continued to lump balls towards Crouch, but the closest they could come was through Maxim Choupo-Moting, who nearly made the most of a Liam O'Brien mistake but saw his low strike blocked heroically by Chris Stokes.
Robins was greeted with a hug from his assistant Ady Viveash on the final whistle. The Sky Blues had done it.
Yellows: Allen 35', Bayliss 57',
Reds:
Goals: Willis 24', Adam 54' (pen), Grimmer '68.
Attendance: 14,199.
Coventry City XI: O'Brien (GK); Grimmer, Willis, Davies, Stokes; Maguire-Drew (Stevenson 62'), Doyle (C), Bayliss, Shipley (Haynes 85'); McNulty, Biamou.
Subs: Burge (GK); Hyam, Maycock, Finn, Ponticelli.
Stoke City XI: Butland (GK); Allen, Wimmer, Zouma, Cameron (Crouch 51'), Sobhi, Ireland (Choupo-Mouting 73'), Adam (Shaqiri '74), Edwards, Biram-Diouf, Berahino.
Subs: Grant (GK); Souttar, Afellay, Fletcher.