Bristol City are fending off Nottm Forest, while Bradford have slipped close to the drop.
Bristol City came from behind to defeat Carlisle 3-1 and fend off the challenge of third-placed Nottingham Forest.
Leyton Orient won 2-0 at Bradford in a relegation 'six-pointer' at Valley Parade that may have consigned The Bantams to League Two football next season.
Play-off hopefuls Carlisle were handed a fifth minute lead against City by Danny Graham but City came back strongly in the second half through Jamie McCombe (48), Enoch Showunmi (65) and Bradley Orr (84).
One more win would guarantee The Robins' Championship football next term but Gary Johnson's side are being pushed all the way by Nottingham Forest, who were 3-0 victors over Bournemouth.
Kris Commons (23 & 54) and David Prutton (66) scored for Forest, while the hosts' progress was aided by the 41st minute dismissal of The Cherries' Neil Young.
Leyton Orient were 2-0 winners at Bradford to all but secure Orient's League One status and push David Wetherall's team perilously close to the drop.
Gary Alexander (62) and Adam Tann (65) won the match for the visitors - the hosts are now four points adrift of safety.
Chesterfield's plight is even worse. The Spireites have been cut six points adrift after Simon Cox's 78th minute winner in Northampton's 1-0 win at Sixfields.
Scunthorpe are just one point away from claiming the divisional title after winning 2-0 at Tranmere, through Gavin Ward's own goal (55) and Billy Sharp (70).
Blackpool and Yeovil consolidated their play-off hopes with wins over Cheltenham and Rotherham respectively.
Keith Southern's 85th minute winner gave Simon Grayson's side victory at Whaddon Road after Robbie Williams (39) and John Finnigan (51, penalty) exchanged strikes, while Marcus Stewart was Yeovil's match-winner in his team's 1-0 success against Rotherham.
Oldham's chances took another blow, however, with a 2-1 defeat to Crewe. Nicky Maynard (25 & 71) scored for the hosts, Richie Wellens (85) replied for Athletic.
The Latics' defeat has opened the door for Swansea to claim the final play-off place and the Welshmen were 2-1 winners over Brighton.
Alex Revell (14) gave Brighton the lead but Daryl Duffy (21 & 41) hit back for the hosts.
Huddersfield defeated Millwall 4-2. Michael Collins (20), Mark Hudson (59) and Luck Beckett (73, penalty, & 79) scored for The Terriers between Darren Byfield's ninth minute opener for the visitors and Alan Dunne's 90th minute consolation.
Gillingham defeated Port Vale 3-2 with Ian Cox (37) and Michael Flynn twice (49 & 53) on target for the hosts. Danny Whitaker (78) and Leon Constantine's 90th minute penalty were consolations for the visitors.
Adam Lockwood (47), Mark Wilson (67) and Lewis Guy's penalty (76) gave Doncaster the points in a 3-0 win over Brentford.
Click below for an individual match summary:
Bradford 0-2 Leyton Orient
Carlisle 1-3 Bristol City
Cheltenham 1-2 Blackpool
Crewe 2-1 Oldham
Doncaster 3-0 Brentford
Gillingham 3-2 Port Vale
Huddersfield 4-2 Millwall
Northampton 1-0 Chesterfield
Nottingham Forest 3-0 Bournemouth
Swansea 2-1 Brighton
Tranmere 0-2 Scunthorpe
Yeovil 1-0 Rotherham
