The bottom three now consist of Bristol City - who drew 1-1 with Queens Park Rangers on Friday night - Crystal Palace and Middlesbrough.
Palace were beaten 4-3 at Preston North End, with the Lilywhites climbing out of the relegation zone as a result. Preston had led 4-1.
They were replaced in the bottom three by Middlesbrough, who were beaten 1-0 at Norwich thanks to a goal from Simeon Jackson.
Portsmouth were not distracted by the concerns over the future as they secured a comfortable 2-1 win at Hull City thanks to goals from David Nugent and Greg Halford.
Although Nick Barmby gave the Tigers hope, but the East Yorkshire side are now clearly in a relegation battle.
Swansea City moved up to fifth with a 2-0 win over Leicester. Marvin Emnes, who turned down a move to Scunthorpe earlier in the week, opened the scoring for the Swans and created the second goal for Scott Sinclair.
Burnley had not lost at Turf Moor this season, but were taken apart by Reading - who returned south with all three points tanks to a 4-0 win.
Coventry City were 3-0 home winners over Burnley, Millwall saw off Derby County 2-0 and Nottingham Forest defeated Ipswich Town 2-0.