Patrick Suffo scored twice to leave Derby without a win in six games at Pride Park. The hosts had only themselves to blame for they had much the better of the first half but failed to take any of the chances they created.
They trailed at the break to goals from Stephen Warnock and Suffo, and although 16-year-old Lee Holmes gave Derby hope early in the second half they rarely looked like getting on terms.
Derby’s other 16-year-old, Tom Huddlestone, had the first shot at goal in the seventh minute, firing a long-range effort which was blocked by Richard Shaw.
But four minutes later the Rams were rocked as Warnock gave Coventry the lead against the run of play.
The midfielder, on loan from Liverpool, was in the right place when Andrew Whing crossed from the right and lashed home a terrific angled volley.
Huddlestone continued his one-man crusade to get Derby on the scoresheet but struck the ball over the crossbar and then had another chance which he headed wide.
Derby thought they had equalised when on-loan Danny Dichio headed the ball into the net but his effort was ruled out for offside.
But Derby’s continued pressure as they searched for an equaliser was wiped out as Sufo struck a second for Coventry.
Richard Jackson’s clearance fell straight to the Cameroon international and he smashed the ball home with Derby goalkeeper Lee Grant off his line.
Derby manager George Burley made two half-time substitutions, Adam Bolder and Pablo Mills replacing Candido Costa and Walton.
And within seven minutes of the restart Derby pulled a goal back when Morris set up Holmes, who drove the ball past Arphexad.
Coventry were not rattled and Youssef Safri forced a fingertip save from Grant with a 35-yard drive.
Suffo wasted two more chances before he wrapped up the points with 11 minutes remaining, getting the better of Michael Johnson and hammering the ball home from close range.
Derby: Grant, Jackson, Walton, Johnson, Zavagno, Costa, Valakari, Huddlestone, Holmes, Dichio, Morris. Subs: Camp, Mills, Bolder, Boertien, Svensson.
Coventry: Arphexad, Whing, Shaw, Konjic, Warnock, Barrett, Safri, Staunton, Doyle, Morrell, Suffo. Subs: Shearer, Pead, Adebola, Davenport, Mansouri.
Referee: R Pearson (Co Durham).
