Ashley Barnes headed the only goal of the game in the seventh minute to move Sean Dyche's side 11 points clear of Derby, who moved into third place following their win at Blackpool and QPR's defeat at Ewood Park.
Derby claimed a 3-1 win over the Tangerines after falling behind to a first-minute goal by David Goodwillie, but the score was quickly cancelled out by Chris Martin in the third minute with Patrick Bamford and Craig Bryson making sure of the away win well before half time.
QPR, meanwhile, dropped points as they bid to claim the second automatic promotion spot as they were beaten 2-0 at Blackburn.
Rudy Gestede and Tommy Spurr both scored for Rovers, who are now four points adrift of the play-off places.
Newly-promoted Leicester looked to have taken their foot off the gas having already secured their place in the Barclays Premier League as they suffered a 4-1 home defeat to play-off hunting Brighton.
A Jose Ulloa double and goals for Stephen Ward and Jesse Lingard had put the visitors 4-0 up before Gary Taylor-Fletcher slotted an 89th-minute consolation score.
Wigan, meanwhile, lost momentum in their play-off push as they fell to a 1-0 defeat to Millwall, Carlos Edwards' 22nd-minute score proving to be their undoing.
Reading, who are also in the hunt for a top-six finish, also stuttered as they were beaten 3-1 by Bournemouth.
The Cherries, who beat QPR 2-1 last time out, claimed victory with two first-half goals for Matt Ritchie and Yann Kermorgant's header on the stroke of half-time, with Hal Robson-Kanu's 75th-minute goal scant consolation for the Royals.
Leeds' torrid form continued as they fell to a 3-0 defeat by Watford which left them eight points above the relegation zone.
Almen Abdi headed Watford to a ninth-minute lead before Ikechi Anya doubled the Hornets' advantage before half-time, with Troy Deeney making sure of the result in the 67th minute.
Bottom side Yeovil fell to a 3-2 defeat by Charlton, with goals for Joel Grant and Kieffer Moore not enough as scores from Astrit Ajdarevic, Dorian Dervite and Marvin Sordell saw the Addicks claim victory.
Doncaster failed to move further clear of the relegation zone and are just four points clear after they were beaten 2-1 at home by Bolton.
Neil Danns put the Trotters ahead in the seventh minute and Joe Mason doubled the lead in the 15th, with Doncaster only hitting back once through David Cotterill's free-kick three minutes later.
Elsewhere, goals for Paul Anderson and Daryl Murphy saw Ipswich claim a 2-0 win at Huddersfield while nine-man Middlesbrough held on to claim a 3-1 win over Birmingham.
Danny Graham and Jacob Butterfield had put Boro 2-0 up before Emyr Huws got one back for Birmingham in the 37th minute. Boro were reduced to nine men in five second-half minutes when Kenneth Omeruo and Ben Gibson were dismissed for second bookable offences late in the game, but Lee Tomlin scored for the home side in the penultimate minute to wrap up the win.
Nottingham Forest salvaged a point despite finishing the game with 10 men as they drew 3-3 against Sheffield Wednesday.
Chris Maguire put the Owls ahead from the penalty spot in the 15th minute after he was fouled by Danny Collins, but Forest hit back through Jamie Mackie's header before Lewis Buxton put Wednesday back in front on the stroke of half-time.
Joe Mattock extended the visitors' lead but Marcus Tudgay claimed Forest's second in the 77th minute before Collins was sent off three minutes later for his second bookable offence. Despite being a man down, Jamie Paterson grabbed the equaliser for the home side with three minutes left on the clock.