Norwich City made it three Championship wins in a row with a thumping victory at Pride Park to continue their resurgence and pile more pressure on Derby head coach John Eustace.
The ragged Rams, now seven points from safety, were pulled apart as first-half goals from Anthony Musaba, Paris Maghoma and Darlin Yongwa put Norwich out of sight.
Substitute Jovon Makama made it four with a thunderous strike after the break as Philippe Clement’s Canaries kept a first clean sheet in 24 games.
The humbling leaves Eustace, who took Derby to within four points of the play-offs last season, staring down the barrel after just one win all season.
To add to second-from-bottom Derby’s woes, they lost top scorer Sammie Szmodics, who limped off with a knee injury in the second half.
Derby, humbled 4-1 by Millwall at the weekend, were pressed into putting out a 12th different back four, including teenage debutant Isaac Gordon at right-back.
The new combination looked uneasy from the start as Norwich took an eighth-minute lead through Musaba.
Jack Stacey’s cross from wide on the right found the unmarked Yongwa at the far post and although Jacob Widell Zetterstrom was able to keep out his header, Musaba – on loan from Fenerbache – was able to tap in his third goal of the season.
Maghoma doubled the lead with a terrific goal, beating the despairing Alex Mowatt three times before curling a lovely shot into the far corner with his left foot from outside the box.
It was the former Tottenham and Brentford man’s third goal in as many games.
Stacey was inches away from making it three a couple of minutes later, striking the post after being put through by Maghoma before Mowatt cleared the rebound acrobatically off the line.
But Norwich’s travelling fans did not have to wait long to celebrate again as Andre Brooks tore down the right and his cross was deflected into the path of Yongwa, who drove the ball home emphatically with his left foot.
Gordon, targeted by Norwich, was withdrawn by Eustace as one of three changes at half-time to try to inject some life into his floundering team.
They did tighten things up to a degree only to leak a fourth when substitute Makama beat the flailing Zetterstrom in the Derby goal from distance.