The win had a huge effect as Oldham and Nottingham Forest both suffered losses.
Oldham remain second in the league, but were beaten 2-1 at home by improving Millwall.
Paul Warne had put the Latics a goal up, but Marvin Williams equalised for the London side and Darren Byfield converted a late penalty for victory.
Forest threw away the chance to make Oldham pay for their loss, with Nathan Tyson the villain at Brighton.
The former Wycombe striker was shown a straight red card for violent conduct at the Withdean.
Despite this, Forest actually took the lead through Jack Lester. But the Seagulls made their extra man county, and took a deserved with thanks to quickfire goals from Dean Hammond and Nick Ward.
Forest dropped to fourth on goal difference after Wayne Andrews earned Bristol City a 1-0 win at Blackpool to climb above them.
Yeovil also missed the chance to close on the league leaders, with Chris Shuker's brace giving fellow play-off chasing Tranmere a 2-0 success at Huish Park.
Swansea remain just outside of the play-off spots following a 2-2 draw at Doncaster, in their first match since Kenny Jackett's resignation as manager.
With Rotherham's plight at the foot of the table looking perilous, Brentford's stunning revival continued with a 2-0 win at Huddersfield.
Charlie Ide and Jo Kuffour scored the goals which hauled them to within three points of safety.
Damien Spencer improved Cheltenham's hopes of survival with a stoppage-time winner over Bournemouth, who drop into the bottom four as a result.
David Wetherall's tenure as caretaker Bradford manager didn't get off to a good start, with Ryan Lowe giving Crewe a 1-0 success at Valley Parade.
Leyton Orient drew 1-1 with Carlisle at Brisbane Road, with Matt Lockwood rescueing a point after Joe Garner had put the Cumbrians ahead.
Phil Picken, Jamie Ward and Wayne Allison were on the scoresheet as Chesterfield thrashed Port Vale 3-0 at Saltergate.