Coventry City's 2-1 defeat to QPR allowed Middlesbrough to draw level with them at the top of the Championship on Saturday.
Coventry looked ready to bounce back from Monday's defeat to Norwich City when Josh Eccles headed Jack Rudoni's excellent delivery home early in the second half at Loftus Road.
A sublime near-post flick from Richard Kone levelled things up in the 66th minute, though, and Nicolas Madsen fired a loose ball into the roof of the net after Carl Rushworth failed to hold onto a cross.
The Sky Blues' once commanding 10-point lead consequently completely evaporated, with Middlesbrough taking full advantage.
Hayden Hackney scored the only goal of the game as Boro secured a 1-0 victory over Norwich at the Riverside; Kim Hellberg's side have now won five straight Championship matches.
Hull City are now just five points adrift of the automatic promotion spots after Lewis Koumas marked his debut with the only goal in a 1-0 triumph at Blackburn Rovers.
Life without Marti Cifuentes did not improve for Leicester City as they fell to a 2-0 loss at home to Charlton Athletic.
Caleb Okoli was sent off after 15 minutes, with Sonny Carey and Lyndon Dykes punishing the Foxes in interim boss Andy King's first game at the helm.
Sheffield Wednesday lost club hero Barry Bannan to Millwall in midweek, and they did not have anything to celebrate at Hillsborough on Saturday against Wrexham; Sam Smith consigned the Owls to a 1-0 loss, keeping the Dragons' play-off push on track.
Data Debrief: Wednesday's woes continue
The defeat to Wrexham was Wednesday's seventh match without scoring a goal – the barren run now standing at 734 minutes.
They have only found the back of the net in 16 of their 30 Championship outings this season.
Coventry still have a bit of a cushion from the play-offs, but they will be kicking themselves if they end up getting caught. Following their loss to QPR, the Sky Blues have lost 17 points from winning positions this season – only Wrexham (20) and Derby County (18) have lost more.