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:
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