This was supposed to be the coronation of Birmingham City as the third tier’s greatest ever side.
Days after securing promotion back to the Championship with six games to spare, minority owner Tom Brady in attendance and more than 40,000 Blues fans having made the trip to Wembley, they had the chance to complete a League and Cup Double and cap one of the greatest seasons in the club's history.
But Peterborough - and Darren Ferguson - just have a way as they pulled off a shock to become the first side to win the EFL Trophy in back-to-back years.
The Posh were brilliant as despite a difficult League One campaign that has them 16th, they repelled Birmingham and scored two great goals through Harley Mills and Hector Kyprianou.
Ferguson has now lifted this trophy as Peterborough manager a joint-record three times, but this was the most special of the lot.
'Yeah, 100 per cent it was,' he said post-match. 'Given the opposition it has to be the best one. You could argue they are one of the best League One teams ever. They’re a good team to watch but today was our day.'
The two sides had met on Tuesday when Birmingham won 2-1 to achieve promotion, yet this was different.
Not only did both sides name much-changed XIs, but Brady and Blues chairman Tom Wagner were whipping up fans before kick off and more than 70,000 flocked to this glorious celebration of the EFL.
Peterborough started well and the electric Kwame Poku was felled following a mazy run.
Academy graduate Mills, playing only his 12th game for the club, stepped up and curled in a delightful free kick.
Mills was involved again in the second as his cross broke to Kyprianou and the Peterborough skipper finished with class to send his side into dreamland.
It was fitting that Mills, who was on loan at sixth tier Enfield Town earlier this season, stole the show given it was Harrison Burrows, another academy graduate and left back, who was the hero in last year’s final against Wycombe.
'He’s got a wand of a left foot and it was a fantastic strike,' Ferguson added. 'And defensively he was outstanding.'
Chris Davies’ side came out firing in the second half and Jay Stansfield had a goal ruled out for offside while Jed Steer made one incredible stop, but Peterborough - whose defence is the second leakiest in League One - stayed firm.
In truth, this was one of Birmingham's worst performances of the season and Wagner and Brady were seen giving the players a pep talk post-match, but Ferguson won't care one bit as he added another trophy to the family cabinet.
‘It wasn’t to be our day,’ Davies reflected. 'We got to the final third consistently but we missed that bit of quality and fell short of what was required to win the match.
'Suffering is part of life and football and you have to take your medicine. We have to learn the lessons and grow from today.'