Matt Smith consigned Bury to the drop with a header 11 minutes from time to hand Oldham a precious victory, which lifted them out of the relegation zone.
Neil Austin's opportunistic goal after Simon Walton's 10th-minute penalty had been saved by Tranmere goalkeeper Owain Fon Williams ensured Hartlepool will live to fight another day. Tranmere could have levelled but Andy Robinson's second-half penalty was saved by Scott Flinders.
Scunthorpe snatched a last-gasp equaliser against Walsall, with Niall Canavan's header cancelling out Will Grigg's 10th goal in nine games to keep the Iron's survival hopes alive.
Fellow relegation-battlers Portsmouth fell to a 3-2 defeat at Brentford after Clayton Donaldson struck with just four minutes remaining. Bradley Wright-Phillips scored twice for the Bees but his efforts were cancelled out by David Connolly and Shaun Cooper.
League leaders Doncaster came from behind to beat Crewe, who had opened the scoring through Max Clayton, with two goals from Billy Paynter.
Bournemouth retained second place with a brace from Brett Pitman and a Jermaine Grandison own goal completing a 3-0 win at Shrewsbury.
In the play-off spots, Sheffield United began life under Chris Morgan with a 2-0 win against Swindon, secured with goals from Chris Porter and Dave Kitson.
Yeovil saw off Stevenage 2-0 with goals from Sam Foley and James Hayter while Leyton Orient kept up their bid for the play-offs with a 2-0 win of their own, beating MK Dons. Gary Sawyer and Kevin Lisbie scored the late goals for Orient, who drew level on points with Walsall.
Elsewhere, Notts County defeated Colchester 3-1, Crawley beat Coventry 2-0 and Carlisle drew 1-1 with Preston.