Birmingham City suffered a defensive nightmare at St Andrew’s as grateful Derby County romped to their best win under Wayne Rooney.
Blues shipped three goals inside the first 25 minutes as Rooney’s Rams bounced back from losing at home to Preston on Saturday – their first defeat since the Derby caretaker boss took sole charge.
Former Blues defender Krystian Bielik cashed in on home keeper Neil Etheridge’s dropped clanger in the 15th minute to volley in from close range.
Inside two minutes, home captain Harlee Dean gave away a needless penalty, which was clinically tucked away by Graeme Shinnie.
Blues then let in a third when they made a shambles of clearing Shinnie’s corner, allowing Colin Kazim-Richards to net from close range.
Youngster Jason Knight completed the scoring after 77 minutes when he neatly tucked away Kamil Jozwiak’s right-wing cross.
It was Derby’s biggest away league win since a 4-0 win at the same venue for Steve McClaren’s team against Gary Rowett’s Blues on Boxing Day 2014.
Derby move out of the Championship’s bottom three for the first time in two months after stretching their unbeaten run in this fixture to nine matches.
Blues, who had also conceded four goals in their previous home game against Middlesbrough, had responded well with a clean sheet on Saturday at Nottingham Forest, another of boss Aitor Karanka’s former clubs.
But any hopes of a repeat evaporated from the moment Etheridge committed his howler, allowing the ball to bounce tamely off his chest as he rose unmarked to gather Shinnie’s right-wing corner.
Bielik was first to respond, lashing in a right-foot volley from 10 yards to mark his first goal for the club. And worse was to follow for the hosts.
Dean was in no danger on the right edge of the Blues box but his clumsy challenge on Louie Sibley gave the Derby youngster the chance to go down and Shinnie did the rest, firing a fine penalty.
Then, from another Shinnie corner from the right, the ball deflected off home midfielder Adam Clayton before Kazim-Richards lunged in to get the final touch from a yard.