Leeds United had their promotion hopes dented as they fell to a controversial 1-0 loss at QPR on Saturday.
Marcelo Bielsa's men have only won one of their past seven Championship matches, a streak that started with their astonishing collapse in a 3-3 draw against Cardiff City.
Leaders West Brom can extend their advantage to four points when they host Stoke City on Monday.
Brentford did not take full advantage of Leeds' loss as they drew 0-0 away to Huddersfield Town, meaning Fulham – winners over Middlesbrough on Friday – remain third.
Swansea City's 2-1 home victory over Wigan Athletic saw on-loan Liverpool prospect Rhian Brewster score his first senior goal.
Blackburn Rovers, Bristol City, Derby County, Millwall and Preston North End were the other winning teams, with the 1-1 scoreline between Birmingham City and Cardiff one of only two draws on the day.
LEEDS' SLUMP CONTINUES
Nakhi Wells' 20th-minute strike for QPR ultimately proved decisive in London.
Leeds were angry that a handball by Wells as he collected Eberechi Eze's deflected free-kick was not spotted by referee Peter Bankes.
Pablo Hernandez hit the post with a set-piece of his own and Patrick Bamford had a second-half penalty saved by Liam Kelly, who conceded the spot-kick, before Kalvin Phillips received a red card in the closing minutes for a foul on Geoff Cameron.
Leeds' advantage over Fulham has been cut to four points with 18 matches still to play.
BRENTFORD HELD AS SWANSEA FIGHT BACK
Brentford started their match knowing a win would put them above Fulham, but they missed the chance to do that and go within three points of Leeds in the process, with Josh Dasilva hitting the post in the closing stages at Huddersfield.
Nottingham Forest have the chance to go level on points with Brentford when they face Luton Town on Sunday, while Swansea sit fifth after coming from behind to beat Wigan.
Nathan Byrne capped a 16th-minute Wigan counter-attack to put the visitors ahead, but Brewster replied inside three minutes before a clever backheel from Andre Ayew after the break won it.
WEDNESDAY THUMPED BY BLACKBURN
Wednesday slumped to an astonishing 5-0 home loss against Blackburn, who saw Lewis Holtby score twice.
Massimo Luongo was sent off after Holtby's opener and Wednesday fell apart from there.
Patrick Bauer headed the winner as Preston came from behind to beat Charlton Athletic 2-1 at Deepdale, Josh Harrop having scored a superb leveller.
Millwall are only outside the play-off positions on goal difference after a 2-0 home win over Reading while Derby beat Hull City 1-0, with Bristol City getting the better of Barnsley by the same scoreline after Niclas Eliasson's dramatic winner.