Hull miss chance to close gap on Cardiff as Posh drop to bottom
Watford moved into second spot after Hull's defeat, while Bristol City climbed off the bottom of the table.
Watford moved into the automatic promotion places with a 2-1 victory over Derby at Vicarage Road.
Striker Matej Vydra set Gianfranco Zola's men on their way with the opener on 35 minutes and Joel Ekstrand doubled the lead after 68 minutes.
Jamie Ward reduced the arrears from the penalty spot 17 minutes from time, but Watford held on for all three points.
Hull dropped down to third after losing 4-1 to Bolton at the Reebok Stadium.
Bolton raced into a 3-0 lead with three goals inside the opening eight minutes from Darren Pratley (2), Mark Davies (5) and Craig Dawson (8).
Robbie Brady pulled a goal back for Hull on 68 minutes, but Dawson ended any hopes of a comeback with Bolton's fourth goal two minutes later.
Bristol City climbed off the bottom of the table with a thrilling 5-3 win over Barnsley at Ashton Gate.
Jon Stead helped himself to two goals while further strikes from Liam Fontaine, Lewin Nyatanga and Steven Davies put the game beyond Barnsley with Chris O'Grady, Tomasz Cywka and Jason Scotland on the mark for the visitors.
Peterborough dropped to the basement after going down 2-0 to Birmingham at London Road.
Nikola Zigic broke the deadlock in the first half and Chris Burke made the game safe with a second ten minutes from time.
Brighton maintained their promotion push with a 1-0 win over Burnley thanks to David Lopez's 20th minute goal.
Sheffield Wednesday boosted their survival hopes with a 1-0 victory over promotion hopefuls Crystal Palace at Hillsborough.
Leroy Lita scored the only goal of the game late on to give Wednesday all three points.
Paul Ince picked up his first point as Blackpool manager after a goalless draw with Leicester at Bloomfield Road.
Chris Wood missed a second-half penalty as Leicester failed to close the gap on the leading pack.
Nottingham Forest picked up their second win of the week with a 2-0 success at ten-man Charlton.
Second-half goals from Radoslaw Majewski and Henri Lansbury earned Billy Davies' side all three points after Yann Kermorgant was sent off for Charlton in the first half for violent conduct.
Huddersfield picked up a precious point after a goalless draw with fellow strugglers Ipswich at the John Smith's Stadium.
Blackburn and Leeds failed to boost their promotion hopes after a goalless draw at Ewood Park.
In Saturday's late game, Millwall ended a run of five straight losses with a 2-1 victory at Middlesbrough to put a dent in the hosts' promotion hopes, with George Friend's own-goal and a Martyn Woolford strike condemning them to defeat.