Chris Martin gave Derby the lead with a 20th-minute goal before Tom Ince added a second on the stroke of half-time.
Brighton remain top after a 1-1 home draw with Cardiff as their nearest rivals failed to capitalise on them dropping two points
Joe Mason had given Cardiff a fifth-minute lead when tapping in from close range, but Dale Stephens equalised with an impressive 38th-minute volley.
Victory would have taken second-placed Middlesbrough top, but they lost 2-0 at Reading, who overtook Burnley on goal difference to go third.
Middlesbrough were enjoying a five-game winning streak, but Danny Williams gave Reading the lead in the opening minute and Nick Blackman scored his eighth goal in as many games with an 88th-minute penalty after being fouled by Fernando Amorebieta.
Hull remain in fifth place following a 1-0 win at Nottingham Forest thanks to Abel Hernandez's close-range effort following a quickly-taken 41st-minute corner
Goals from Demarai Gray and Jacques Mahoma saw Birmingham extend their unbeaten away record this season with a 2-0 victory at Leeds, which lifted them into fourth place.
Wolves climbed up to ninth place with a 3-0 defeat of Huddersfield in the lunch-time kick-off at Molineux
Kevin McDonald put Wolves ahead in the 20th minute with a classy finish from 20 yards before Benik Afobe struck in the 66th and 88th minutes.
Jay Emmanuel-Thomas scored a 94th-minute winner to end QPR's four-game winless run and seal a 4-3 home win against Bolton.
Early goals from Gary Madine and Liam Feeney gave visitors Bolton a two-goal lead but Emmanuel-Thomas scored his first in the 13th minute and Leroy Fer equalised on the stroke of half-time.
QPR edged in front through Tjaronn Chery in the 62nd minute and although Wellington Silva equalised for Bolton in the 85th minute, Emmanuel-Thomas fired a stoppage-time winner.
Blackburn's Jordan Rhodes scored twice against former club Ipswich at Ewood Park in a 2-0 home win.
Rhodes' first was via the penalty spot in the 12th minute after Larsen Toure's foul on Hope Akpan and he struck again four minutes later.
Sheffield Wednesday moved up to 10th place after a 3-1 home win against Preston.
Kieran Lee gave Wednesday the lead just before half-time, Daniel Pudil added a second nine minutes into the second half and although Alan Browne replied for Preston, Lewis McGugan scored six minutes into added time.
Bristol City remain bottom after being denied three points by Daniel Powell's stoppage-time equaliser for MK Dons in a 1-1 draw.
The hosts had taken an early lead through Jonathan Kodjia before Powell curled home in the fourth minute of added time.
Source : PA