Preston moved level on points with Cardiff at the top of the Championship thanks to a hard-fought 1-0 victory over Leicester at the Walkers Stadium.
Patrick Agyemang's 15th-minute tap-in after a flowing North End move proved to be the only goal of the game as both sides spurned chances.
The win closed the gap on the Bluebirds after their surprise 1-0 home defeat by QPR yesterday.
Birmingham wasted the chance to join them on 36 points after the day's early kick-off saw them draw a controversial West Midlands derby 1-1 with Wolves at St Andrews.
Gary McSheffrey gave City the lead with a fine drive but Wolves equalised late on thanks to Jody Craddock's header.
Blues were angered by referee Mark Halsey after he played on in the build-up to Craddock's goal when Gary Breen appeared to foul Sebastian Larsson, and he also disallowed a potential late winner from Nicklas Bendtner.
Burnley remain fourth despite a heavy 3-0 defeat at fellow promotion-chasers West Brom, who were two goals ahead within seven minutes thanks to Jason Koumas (5) and Nathan Ellington.
Darren Carter added another in the last minute of the first half to clinch the points, before Frank Sinclair was sent off for the Clarets after picking up two bookings.
Derby leapt up to fifth in the table after former player Steve Howard returned to haunt Luton, who have now suffered six straight league defeats after today's 2-0 loss.
Jon Stead, on loan from Sunderland, gave County the lead in the 72nd minute at Kenilworth Road.
Howard (75), who left the Hatters during the summer, added a second to end a turbulent weeLuton manager Mike Newell in the worst possible fashion.
Leeds remain in the relegation places after a morale-sapping 3-0 defeat by Southampton at Elland Road.
Grzegorz Rasiak (29) gave George Burley's Saints the lead, before Czech international Rudi Skacel (69) made it two.
Rasiak (75) completed the rout as Dennis Wise suffered his first home defeat since taking over as United manager.
Crystal Palace eased their own relegation fears with a 2-0 win over Barnsley, who remain second from botom.
Peter Taylor's side eased the pressure on their manager thanks to first-half goals from James Scowcroft (16) Clinton Morrison (32).
Southend stay bottom after their 14th game without a league win, although they did claim a 1-1 draw with Plymouth.
Bojan Djordjic handed Argyle a fourth-minute lead before Mark Gower (59) levelled. The Shrimpers are three points adrift.
Hull remain just clear of the relegation places despite a 2-0 defeat by Stoke at the KC Stadium which saw the Potters rise to seventh.
Danny Higginbotham gave City the lead in the second minute before midfielder Darel Russell sealed victory with 10 minutes left.
A 3-1 win for Sunderland over Colchester lifted the Black Cats into mid-table.
Stephen Elliott was the home side's hero with a brace (45 and 53), though Chris Iwelumo (79) made it an uncomfortable end for Roy Keane's side before David Connolly's injury-time third.
Sheffield Wednesday had Wade Small and Chris Brunt sent off as they lost the lead to crash 3-1 at Coventry.
Brunt (22) had given Wednesday the lead, but a Madjid Bougherra own goal (25) and Leon McKenzie's second-half double strike (51 and 55) gave City the points.
However, manager Micky Adams' afternoon was marred by a suspected broken leg suffered by Don Hutchison.