As things stand, Darren Ferguson's side are seven points clear in second place, with just four matches of the season left to go. However, Tuesday night's shock 1-0 loss to Gillingham was a real wake-up call for the Posh, who can't afford any complacency at such a crucial stage of the season.
Next up, Peterborough will look to bounce back this weekend, when they travel to take on fellow promotion-chasers Charlton Athletic - a side they beat 2-1 when they last met back in January - at The Valley.
Here's the latest rundown of the current League One promotion odds, after another action-packed night of third-tier football:
. PETERBOROUGH, ENGLAND - FEBRUARY 09: Jonson Clarke-Harris (R) of Peterborough United celebrates after scoring their first goal during the Sky Bet League One match between Peterborough United and Ipswich Town at Weston Homes Stadium on February 09, 2021 in Peterborough, England. Sporting stadiums around the UK remain under strict restrictions due to the Coronavirus Pandemic as Government social distancing laws prohibit fans inside venues resulting in games being played behind closed doors. (Photo by David Rogers/Getty Images)
Peterborough United's latest promotion chances revealed following shock midweek loss Photo: David Rogers
. Gillingham - current odds: 500/1
Stranger things have happened, but it really would take a miracle now for Gillingham to claw their way into the top six, and then somehow win the play-offs. Photo: James Chance
. Accrington Stanley - current odds: 350/1
The table is so tightly-packed that John Coleman's side, currently in 12th place, could potentially get promoted this season. That said, it's very, very unlikely at this stage. Photo: Pete Norton
. Doncaster Rovers - current odds: 100/1
Long, long odds, these are. Donny would need to win both of their two games in hand to stand a chance of making the play-offs, and hope that results elsewhere go their way. Photo: Joe Portlock
1. Gillingham - current odds: 500/1
Stranger things have happened, but it really would take a miracle now for Gillingham to claw their way into the top six, and then somehow win the play-offs. Photo: James Chance
2. Accrington Stanley - current odds: 350/1
The table is so tightly-packed that John Coleman's side, currently in 12th place, could potentially get promoted this season. That said, it's very, very unlikely at this stage. Photo: Pete Norton
3. Doncaster Rovers - current odds: 100/1
Long, long odds, these are. Donny would need to win both of their two games in hand to stand a chance of making the play-offs, and hope that results elsewhere go their way. Photo: Joe Portlock
4. Ipswich Town - current odds: 66/1
Without a win in five matches, the Tractor Boys don't look like they'll be going up this season. It'll be interesting to see how heavily they invest in new players this summer, following their recent £40m takeover. Photo: Pete Norton