DERBY County lead Doncaster Rovers 1-0 at half-time in their bid for a seventh successive win.
Jamie Ward's seventh goal of the season put the Rams ahead after 13 minutes.
It could have been better for Steve McClaren's side, though.
They lost skipper Richard Keogh to injury before Chris Martin saw a penalty saved.
Martin glanced a header wide from Ward's eighth-minute free kick but Derby opened the scoring shortly afterwards.
Doncaster failed to deal with Craig Forsyth's high ball forward, allowing Martin to play an incisive pass to Ward, who finished low past Ross Turnbull from eight yards out.
Keogh appeared to fall awkwardly on his knee following an aerial challenge and while he was off the pitch, Richie Wellens stung the palms of Lee Grant with a 25-yarder.
Keogh tried to continue but was replaced by Michael Keane with 25 minutes on the clock.
The Rams were awarded a penalty when Martin was felled by Luke McCullough in the box.
But Martin's 36th-minute spot kick was saved well by Turnbull, diving low to his right.
