A Sammie Szmodics double and goals from Jonson Clarke-Harris, Jack Marriott and Jack Taylor meant Neil Critchley’s side ended the season with back-to-back defeats.
The Seasiders, who opted to rest a number of players, were never really at the races and the scoreline could easily have been far greater.
The only positive was the debut handed to youth-team products Luke Mariette and Jake Daniels, who were given time off the bench in the second-half.
Despite the poor result, Blackpool have still enjoyed an excellent first season back in the Championship - finishing in 16th, 23 points clear of the bottom three.
As for Posh, their relegation to League One had already been confirmed before today’s season finale, but McCann was pleased to at least end the campaign on a high.
“It took us a while to get going in the first 15 to 20 minutes, it felt like a bit of a pre-season friendly. There was quite a low tempo,” he said.
“But after that, we got a grip of it, we pressed higher and we got control of the game a little bit.
“It was a great goal to open the scoring and in the second-half I just told the players to go and enjoy the game and end the season on a real positive. Can we get more goals?
“We’re playing against a very organised Blackpool team who have done really well considering they came up last year through the play-offs.
“But all in all it was a really good day’s work.
“When we lost the ball I was really happy with our reaction. Our counter-press was good and we were on the front foot with everything we did. We limited them to very few opportunities at our goal.
“Today was about sending home our fans happy with a bit of positivity, so this was for them.
“We felt a bit embarrassed, a bit ashamed walking around at the end, but we’ve shown our appreciation to the fans. Hopefully next season we can walk around with a different feeling.
“This leaves us with a real sense of positivity heading into the summer break.”