Sunderland goalkeeper Anthony Patterson made a costly error as the Championship promotion chasers crashed to a surprise 1-0 defeat against struggling Hull on Saturday.
Patterson flapped Joe Gelhardt's corner into his own net in the 18th minute at the Stadium of Light.
That was enough to condemn fourth-placed Sunderland to consecutive league defeats for the first time this season.
The Black Cats are eight points adrift of second-placed Sheffield United, who face leaders Leeds on Monday.
West Bromwich Albion climbed back into the play-off places with a 2-0 win over Oxford at the Hawthorns.
Alex Mowatt's 11th-minute goal and John Swift's strike deep into second-half stoppage time moved Tony Mowbray's side up to fifth.
Josh Coburn tapped in Millwall's stoppage-time winner after missing a penalty just minutes earlier in a dramatic 1-0 victory at second-bottom Derby.
Jack Rudoni and Bobby Thomas scored in the first half for Coventry as Frank Lampard's side stepped up their play-off bid with a 2-1 win over Preston.
Will Keane halved the deficit, but the hosts ended their 17-year wait for a league victory over Preston.
Norwich also improved their play-off prospects by beating Stoke 4-2 at Carrow Road for a first win in four matches.
In-form striker Josh Sargent made it seven goals in six games with a well-taken double, with Lewis Dobbin and a Junior Tchamadeu own goal completing the scoring.
Portsmouth moved nine points clear of the relegation zone as they beat QPR 2-1 at Fratton Park for a third successive victory.
Josh Murphy and Matt Ritchie scored for Portsmouth early in the second half before Jimmy Dunne replied for QPR.
Plymouth substitute Muhamed Tijani scored a 67th-minute equaliser as third-bottom Argyle rescued a 1-1 draw at home to relegation rivals Cardiff.
Fourth-bottom Cardiff swept into a 14th-minute lead through Yousef Salech but were reduced to 10 men when Dimitrios Goutas was sent off eight minutes after the break.
Alan Sheehan's second spell in caretaker charge of Swansea got off to a dream start after goals from Zan Vipotnik, Myles Peart-Harris and Liam Cullen earned them a 3-0 victory over sixth-placed Blackburn.