Ben Turner's first Football League goal saw Coventry maintain their unbeaten start to the npower Championship campaign as midlands rivals Derby were beaten 2-1 at the Ricoh Arena.
The big defender headed the winner after 80 minutes to temporarily send the Sky Blues top of the table.
Dean Moxey had marked his return to the Derby starting line-up with a goal early in the second half to cancel out Lukas Jutkiewicz's first-half penalty.
American forward Conor Doyle was handed his full Derby debut and was one of two changes to Nigel Clough's side along with Moxey.
Doyle replaced Luke Varney, who could be set for a move away from Pride Park, while Moxey came in for Tomasz Cywka after he fractured his cheekbone against Cardiff last weekend.
However, Cywka was on the bench and sported a protective mask during the warm-up.
Keiren Westwood replaced Iain Turner in goal in the only change made by Coventry boss Aidy Boothroyd.
The Sky Blues had an early chance when Freddy Eastwood sent a looping header over the crossbar from Gary McSheffrey's fifth-minute cross.
Derby came close to scoring after 27 minutes when Westwood's poor clearance dropped to Paul Green, who sent a lob goalwards from 40 yards only to see defender Turner head the ball off the line.
Gareth Roberts needlessly headed behind for a corner and the same player cleared Lee Carsley's shot off the line.
Coventry took the lead in the 33rd minute after Dean Leacock was judged to have fouled McSheffrey inside the area.
Jutkiewicz, whose last-minute penalty salvaged a 2-2 at Watford last weekend, blasted the spot-kick past Stephen Bywater. The summer signing from Everton was then replaced by Clive Platt shortly afterwards because of injury.
The hosts should have extended their lead just before the break but McSheffrey sliced his shot in front of goal from Eastwood's right-wing cross.
Derby were level after 52 minutes. Rams skipper Robbie Savage, making the 500th League appearance of his career, found John Brayford on the overlap down the right and his cross was steered home by Moxey from 12 yards out.
David Bell and Eastwood had goalbound efforts blocked as Coventry tried to re-establish a lead. Kris Commons and Moxey went close at the other end.
Richard Keogh headed wide midway through the second half as the Sky Blues continued to look dangerous.
Their pressure paid dividends 10 minutes from time. Bywater parried a headed effort from substitute Platt and following the resulting corner, Turner glanced a header into the bottom corner from Carsley's right-wing cross.
It took a fine save from Westwood late on to preserve Coventry's lead. The Republic of Ireland international reacted quickly to tip a mishit shot from Moxey over the crossbar.
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