Grant McCann had fired the home side into an early lead and they maintained their advantage until the 80th minute when two goals in the space of three minutes kept Palace top and stretched their unbeaten run to 13 games.
Holloway said: "You never say never with the lads that I have in that dressing room and it is a great place to be at the minute.
"We were terrific from start to finish and I always believed that if we could get ourselves level a second goal might follow.
"That's exactly how it turned out and the manner of our second goal, which started from a punch from my keeper, was fantastic.
"Peterborough defended really well and Darren (Ferguson) will be disappointed because he won't feel he owed us anything, but that stats will tell you that we deserved the points.
"Someone said we are showing Championship-winning form, but that can soon change. We just have to try to keep it going."