Unlike last season, when Derby County began strongly before ending a lowly 19th, their manager, Nigel Clough, is convinced his current squad has the wherewithal to maintain a promotion challenge. Worryingly for the Rams, however, while he may yet prove to be correct, the pattern is beginning to repeat itself. His team were second best to Cardiff City by a considerable margin and have now won only one of their last seven matches.

The Bluebirds, who on this evidence look rather better equipped to sustain a push for the Premier League, are now perched nicely in fifth.

"Injuries are part of the problem at the moment but we were a little bit off it and Cardiff were very, very good; they looked a very accomplished side," Clough said.

The absence of a clutch of senior players meant another start up front for Mason Bennett, who at 15 years and 99 days became Derby's youngest ever starter when he took the field against Middlesbrough at the Riverside the weekend before last. Cardiff also made changes, Malky Mackay leaving out the 20-year-old Joe Mason – a scorer in each of City's last two games – and opting for the experience of Kenny Miller instead.

It was Bennett who looked the livelier early on as Derby tried to build up some momentum but Clough's side soon found it hard going against Cardiff's savvy five-man midfield. It was almost 15 minutes before the match produced its first genuine attempt on goal, a bright move down the Cardiff left resulting in a Filip Kiss shot from 22 yards that Frank Fielding saved comfortably enough.

Five minutes later, however, the Slovak midfielder did beat the Derby goalkeeper with a smart shot on the turn inside the County penalty area after Mark Hudson had headed Peter Whittingham's free-kick back across goal.

Cardiff should have doubled their lead within minutes, when a swift counterattack resulted in Craig Conway sprinting clear down the left. Fielding held his ground before blocking the winger's shot.

Hard though Derby were trying, they found it almost impossible to retain possession and all that changed immediately after the break was that Cardiff became even more dominant. Whittingham's volley from the edge of the penalty area flew only a couple of inches outside Fielding's right-hand post two minutes after the restart, and Aron Gunnarsson's powerful right-foot drive soon afterwards was not much further away.

When Ben Turner headed straight at Fielding, Cardiff must have begun to wonder whether they were destined to let the win slip away but, appropriately on a night when Derby gave the ball away for fun, it was an own-goal take made the points safe. Miller glanced on a corner and Kilbane's attempt to head clear put the ball in his own net. That Whittingham beat the offside trap and then Fielding to make it three a few minutes later ensured the scoreline was an accurate reflection of the game.

"Like any manager you always strive for more but I've been delighted with the way we're applying ourselves so far this season," Mackay said. "We were terrific tonight. We started well, controlled the ball in the first half and then were very professional in the way we closed the game out."