Darren Ferguson told his triumphant players there is no room for sloppiness in the race to escape relegation.
Ferguson was thrilled with his side's performance as they survived a late scare to sink Bolton 5-4 in a thriller at soggy London Road.
Only an inferior goal difference keeps Posh at the foot of the table after they secured back-to-back wins for the third time during a season in which all their victories have arrived in pairs.
Ferguson said: "It was a bit like the old days. We were outstanding for the vast majority of the match, but bang-average in the last few minutes.
"The game should really have been over at 5-2 and we can't afford the make the sort of lapses in concentration that we did late on.
"We are in a battle to stay up and goal difference could be a factor so we cannot afford to give soft goals away, but I don't want to be too critical of my players after producing such a good performance against a team that were in the Premier League this time last year."
Bolton boss Dougie Freedman said: "I'm obviously very disappointed with the result.
"We knew that individual mistakes could well influence a game played in very testing conditions and that is an area in which we let ourselves down.
"We weren't in the game for the opening 20 minutes and full credit to Peterborough for the way they started.
"But we were much-improved in the second half and it was pleasing to see the players continue to show such desire even when it looked as though the match had gone."