Second-half goals from Ephron Mason-Clark and Nathanael Ogbeta wrapped up the win to leave Posh just one behind behind Bolton Wanderers and Derby.
Our photographer David Lowndes was on hand as ever to capture just some of the fans who were there.
Take a look and see who you can spot.
Keep up-to-date with the latest Posh news here.
1. Posh 2 Derby 0
Peterborough United fans are pictured watching the crucial win over Derby County. Photo: David Lowndes
2. Posh 2 Derby 0
Peterborough United fans are pictured watching the crucial win over Derby County. Photo: David Lowndes
3. Posh 2 Derby 0
Peterborough United fans are pictured watching the crucial win over Derby County. Photo: David Lowndes
4. Posh 2 Derby 0
Peterborough United fans are pictured watching the crucial win over Derby County. Photo: David Lowndes
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