Patrick Bamford swept home the winner after nine minutes when he latched onto Luke Ayling's cushioned header.
Marcelo Bielsa's second-placed side are two points behind leaders Norwich - winners on Friday - while Bristol City dropped down to seventh.
Third-placed Sheffield United remain hot on the heels of Leeds after they beat 10-man Rotherham 2-0 at Bramall Lane in the early kick-off.
Jack O'Connell's opener and Mark Duffy's fifth goal of the season ensured a comfortable victory for the Blades after Rotherham captain Will Vaulks was sent off in the first half.
West Brom's slim hopes of breaking into the automatic promotion places took a blow as they drew 1-1 with bottom side Ipswich.
Stefan Johansen's deflected goal after four minutes seemingly set the Baggies on their way but Jon Nolan headed home an equaliser for the Tractor Boys just after half-time.
Derby moved into the play-offs - at the expense of Bristol City - despite being held to a 1-1 draw at home to Sheffield Wednesday.
Bradley Johnson's 10th-minute header put the Rams into the lead but Dominic Iorfa equalised after 57 minutes for mid-table Wednesday.
Brentford fought back to beat promotion-chasing Middlesbrough 2-1 at the Riverside Stadium.
Ashley Fletcher had put Boro in front after six minutes but a Ryan Shotton own goal and Said Benrahma's 73rd-minute winner kept the hosts in fifth place.
Bolton boosted their survival hopes with a 2-1 home win over fellow strugglers Millwall.
Pawel Olkowski broke the deadlock after 48 minutes and the Trotters doubled their advantage through Gary O'Neil on the hour mark.
Wanderers are now five points adrift of safety, while Millwall - who grabbed a late consolation through Lee Gregory - are just a point above the drop zone.
Reading rescued a stunning 3-2 victory against fellow strugglers Wigan at the Madejski Stadium.
Nick Powell put the Latics in front in the 20th minute but John Swift levelled the scores in first-half added time.
Joe Garner's second-half effort looked to have won it for Wigan before late goals from Modou Barrow and Yakou Meite turned the game on its head.
Daniel Johnson's second goal in as many games gave play-off hopefuls Preston - who had Darnell Fisher sent off in added time - a battling 1-0 victory at Blackburn.
Nottingham Forest beat Hull 3-0 at the City Ground courtesy of second-half goals from Joao Carvalho, Karim Ansarifard and a Joe Lolley penalty.
Elsewhere, Stoke's Sam Clucas and QPR's Grant Hall were sent off in an otherwise forgettable 0-0 draw at Loftus Road.