Grant McCann is out to inspire another immediate Championship return after Peterborough suffered relegation on a “sad day” after a 1-0 defeat at home to Nottingham Forest.
Their inevitable relegation was confirmed by defeat at the hands of a Forest side still dreaming of promotion to the Premier League.
Sam Surridge headed the only goal on the stroke of half-time from Brennan Johnson’s cross when capping a terrific counter-attack started by Philip Zinckernagel.
McCann said: “It’s a sad day for everyone connected to the football club.
“People work tirelessly behind the scenes and fans pay their hard-earned money every single week, home and away, but we just haven’t been able to deliver.
“I can’t thank the players enough for the attitude, effort and determination they have put into the 12 games since I’ve been here.”
Posh saw good chances go begging in both halves as Ricky-Jade Jones and Harrison Burrows were denied by goalkeeper Brice Samba as their stay in the second tier ended after just one season.
Posh chief McCann, who returned for a second spell after Darren Ferguson quit in February, was in charge of Hull when they tumbled out of the Championship in 2020, but then masterminded a League One title for the Tigers the following campaign.
And he is already setting his sights on turning disappointment to delight in similarly spectacular fashion at Posh next term.
McCann added: “A lot of the players won’t have been in this position before and felt this sort of pain, but they have to feel it and use it to their advantage to ensure the comeback is stronger than the failure.
“We all want to be a sustainable Championship club, but now we have to focus on getting back into this league.
“I’ve had this experience before at Hull not so long ago. We dusted ourselves down to bounce straight back and hopefully we can do that here too.
“People think League One is easy. It’s not. It’s a really tough league full of massive clubs, but I think we can have a really successful season.”
Forest boss Steve Cooper refused to take a play-off spot for granted despite them needing only one more point from four remaining games to seal the deal.
Cooper said: “We weren’t at our purest by any means, but we showed enough quality to get the job done.
“We stood up to everything Peterborough threw at us really well, we stuck to our way of playing and scored a brilliant goal.
“We had somewhere around 3,700 fans here and it sounded like 37,000 at times with the noise they make. They played a massive part in getting us over the line.
“Fair play to Peterborough…they have some good young players and really put up a good fight today. We’ll be happy to get back on the bus with the win.
“I’ve got a lot of respect for Grant and he knows that as we spoke even before he came here.
“We still have work to do and need to get down to Fulham for the next game in the best shape possible.
“They’re the best team in the league and deserve to be promoted, but we want to play against the best to see where we’re at.”