Argentinian forward Emanuel Villa netted a hat-trick as Derby set up a Carling Cup fourth-round home date with Leeds following their 4-1 victory over Brighton.
The Rams, who have now lost just one of their last 12 games, took the lead in the 28th minute.
Poland striker Przemyslaw Kazmierczak, on loan from Porto, delivered a cross which Albion goalkeeper John Sullivan came to collect. But under pressure, he dropped the ball and Villa - who went from villain to hero after scoring at both ends in the East Midlands derby against Nottingham Forest on Sunday - was on hand to prod home from six yards.
The Rams doubled their advantage six minutes later when Nathan Ellington slotted past Sullivan after Dean Leacock's ball had put him clean through. But Brighton responded immediately and cut the deficit within two minutes when Tommy Elphick headed home Kevin Thornton's corner.
However, Villa put the result beyond doubt in the 73rd minute, heading home a cross from substitute Gary Teale, before claiming his third with a neat finish from six yards three minutes from time.
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