Karleigh Osborne's 74th-minute own goal was enough to hand Brighton a 1-0 victory over Brentford at Griffin Park and send Gus Poyet's Seagulls seven points clear at the top of npower League One.
But below them the automatic promotion race was blown wide open by second-placed Bournemouth's shock 2-0 defeat at Exeter, which allowed those clubs immediately below them to capitalise.
Brighton have two games in hand over the two teams immediately below them and Osborne's mistake has surely now confirmed that the south-coast club will be returning to the Championship in May. But Bournemouth will be made to sweat in their bid to join them, with goals from Jamie Cureton and Richard Logan giving the Grecians a well-deserved victory at St James' Park.
To cap a bad night for Bournemouth, the clubs in play-off positions at the start of the night all won, with Huddersfield closing the gap to a single point as goals from Benik Afobe and Gary Roberts earned a 2-1 win over Rochdale.
Peterborough are also within striking distance after Charlie Lee's 57th-minute winner at Notts County while Southampton, currently in fifth place but with games in hand on those above them, eased past Yeovil 3-0. Lee Barnard hit a goal in each half for the Saints and Alex Oxlade-Chamberlain added a third in the 67th minute to boost their automatic promotion hopes.
Milton Keynes Dons tightened their grip on the final play-off slot with a 2-0 win over fast-fading Charlton, who are now without a win in six. Daniel Powell and Sam Baldock scored for the Dons.
Leyton Orient, who sit eight points behind Milton Keynes but with four games in hand, helped their cause with a 2-0 win at Walsall, who slipped back into the relegation zone as a result.
Dagenham & Redbridge wriggled out of the drop zone thanks to Bas Savage's 11th-minute winner against Colchester, while Swindon replaced Plymouth at the bottom after Rory Fallon's early winner for Argyle at Home Park.
Chris Lines scored a potentially priceless 19th-minute winner for Bristol Rovers against Tranmere at Prenton Park. Rovers stay in the relegation zone but are now within two points of safety.
Francois Zoko scored the only goal of the game as 10-man Carlisle beat Hartlepool at Brunton Park despite the 44th-minute sending-off of Liam Noble. Chris Sedgwick's double helped Gary Megson's Sheffield Wednesday edge to a 3-2 win over Oldham at Boundary Park.
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