Derby suffered a shock 2-1 home defeat to Port Vale in a controversial match at Pride Park.
James Collins put Derby ahead in Paul Warne’s first home league game as manager, but was later sent off as Vale hit back through an Ellis Harrison penalty and a James Wilson strike.
Derby hit Vale on the break in the fifth minute with Tom Barkhuizen crossing for Collins to fire past Jack Stevens from 12 yards.
Stevens denied Nathaniel Mendez-Laing but Vale wasted a great chance when Tom Conlon dragged his 15th minute penalty wide after Dan Jones was caught by Barkhuizen.
Vale showed plenty of spirit but Derby almost made it two in the 35th minute when Lewis Dobbin shot wide from 10 yards.
The visitors were awarded another penalty in the 55th minute when Richard Stearman handled from a corner and this time Harrison made no mistake.
Collins was shown a straight red three minutes later after a clash with Nathan Smith and Vale won it in the 66th minute when Harrison set up Wilson to score from 15 yards.