It was not a classic match but then crunch games at this level rarely are, with the smallest glimpse of finesse invariably answered by a thunderous tackle.
Sunderland, in the event, drew first blood, but Michael Gray's 34th-minute strike, his swerving shot from the edge of the penalty area after Derby had failed to clear their lines at a corner, was cancelled out within 60 seconds.
Marco Gabbiadini, captaining the side, led the recovery against one of his three former clubs. He took advantage of Dean Sturridge's pass as Sunderland dropped their guard, although the goalkeeper Alec Chamberlain got a hand to his shot. Another minute later, Sean Flynn rattled Chamberlain's left-hand post from 25 yards.
Sunderland, beaten only once in 15 matches before yesterday, regained their poise and looked capable of regaining their lead, too, early in the second half. The substitute Gareth Hall's through-ball was half a yard from setting up Craig Russell, and Richard Ord's looping flick brushed a post with the goalkeeper, Russell Hoult, beaten.
But Ord conceded a penalty in the 64th minute, with a clumsy challenge on Sturridge, and that handed Derby the initiative. Ron Willems, the Dutch striker, converted the kick, forcing Sunderland to drive forward in numbers and leave themselves vulnerable at the back.
That played into Derby's hands. After Hoult had saved well from Phil Gray's header, Derby waited patiently for the chance to put the issue beyond doubt. It came from a break led by Darryl Powell, whose ball to Gabbiadini was passed on unselfishly to Sturridge. Perfectly placed 10 yards out, he gave Chamberlain no chance in claiming his sixth goal in eight matches. Victory capped a remarkable rise by Derby from 17th place to first in little more than six weeks.Reuse content