Bristol Rovers remain in the relegation zone as they were soundly beaten 4-1 by York City.
Four first-half goals, including a brace from striker Ashley Chambers, humiliated Mark McGhee's men at Kit-Kat Crescent.
Aldershot also scored four to beat Rochdale 4-2 and put more distance between them and the foot of the league.
At the other end of the table, Gillingham missed a chance to extend their lead, but did come back from two goals down to grab a 2-2 draw against Fleetwood Town.
© PA Photos
This missed opportunity was due to Port Vale and Cheltenham, second and third respectively, sharing the spoils in a 1-1 draw at Whaddon Road.
Elsewhere, Rotherham and Wycombe picked up useful away wins, the latter despite striker Matt McClure scoring and then getting sent off in a 2-0 victory over Accrington Stanley.
Results in full: Exeter 1-1 Plymouth, Morecambe 1-1 Oxford United, Accrington Stanley 0-2 Wycombe Wanderers, AFC Wimbledon 0-1 Rotherham, Aldershot 4-2 Rochdale, Cheltenham 1-1 Port Vale, Chesterfield 1-1 Burton Albion, Dagenham & Redbridge 1-0 Barnet, Gillingham 2-2 Fleetwood Town, Southend 2-2 Bradford, Torquay 1-1 Northampton, York City 4-1 Bristol Rovers
