Peterborough's front two of Craig Mackail-Smith and Aaron McLean, ably assisted from the left by George Boyd and from the right by Chris Whelpdale, tore injury-hit Cheltenham Town to shreds at times.
Robins goalkeeper Scott Brown had already saved from Boyd before the carnage began in the third minute, Boyd again running onto a pass from McLean before driving in a deflected shot.
Mackail-Smith had a goal disallowed for offside then saw a shot saved by Brown but Cheltenham hauled themselves level with a penalty three minutes into the second half when Ashley Vincent was pushed over by Charlie Lee.
Vincent got up to bury the spot kick himself but Lee made amends on the hour mark, heading in from a Dean Keates corner at the near post.
Mackail-Smith made it 3-1 three minutes later when he latched onto a pass from McLean and rounded the goalkeeper.
Back came Cheltenham and this time Vincent turned provider, supplying Elvis Hammond with a pass just inside the area and the striker turned sharply before beating goalkeeper Joe Lewis with a low drive in the 67th minute for his first goal for the club.
However, Posh restored their two goal advantage with 15 minutes left when some admirable persistence from Mackail-Smith down the left resulted in a cross that defender Alan Wright inadvertently turned past his own goalkeeper.
There were yet more twists and turns left in this remarkable match as Cheltenham substitute Lloyd Owusu made it 4-3 four minutes from the end when he flicked on a long throw from Lee Ridley. Lee headed the clear but only as far as Owusu, who followed in to score.
But no sooner had play re-started than Peterborough were celebrating again. Right from the kick-off McLean sprinted onto a long ball from defender Craig Morgan before blasting a shot beyond Brown.
Three minutes into time added on Cheltenham striker Barry Hayles was given his second red card of the season, this one for a stamp on Tom Williams, then in the dying seconds Whelpdale added a sixth goal, touching in at the far post from a Boyd cross.