Britt Assombalonga helped himself to a perfect late birthday present with the first hat-trick of his career a day after turning 21.
And striker partner Shaun Jeffers toasted a first Posh start by grabbing his first two goals for the club when striking in stoppage time at the end of each half.
The result was never in doubt after Posh, who also won 5-0 at Tranmere in a league clash in August, turned their domination into goals late in the first half.
Moore admitted: "You can't come to a place like Peterborough and defend how we did in the second half.
"We were so naive it got embarrassing and we can count ourselves lucky that Peterborough didn't get more than five goals.
"I want to apologise to the people who travelled down and paid good money to watch that.
"It was unacceptable and they can rest assured the lads have had their ears rapped in the dressing room.
"We've got to come back here in a few weeks in the league and hopefully we'll be in a lot stronger position then."
- Sports & Recreation
- Shaun Jeffers
- Britt Assombalonga