AFC Wimbledon stunned Premier League new boys Ipswich Town on penalties to reach round three of the Carabao Cup.
Conor Chaplin headed a late equaliser for Ipswich to force a penalty shootout, but the Dons clinched it 4-2 after Owen Goodman saved from Jack Taylor and Omari Hutchinson.
Ali Al-Hamadi gave Town a third-minute lead against his former side with a free header from Conor Townsend’s corner before Omar Bugiel nodded in Jake Reeves' free-kick to equalise before the break.
Matty Stevens rose highest in a crowded goalmouth to head the Dons ahead before Chaplin headed in with just four minutes left.
After defeats to Liverpool and Manchester City in a daunting start to their Premier League return, Ipswich failed to lift their season as Isaac Ogundere struck the winning penalty to send the fourth-tier Dons into dreamland.
Ipswich boss Kieran McKenna fielded six debutants amid 10 changes, including Chiedozie Ogbene, hours after his move from Luton, and Manchester City loanee Kalvin Phillips.
The sides had met in League One as recently as three seasons ago, but Ipswich had seemingly underlined the new gulf between them, dominating first-half possession and settling the nerves early through Al-Hamadi.
Yet the Tractor Boys struggled to fashion further chances before the break and the hosts could have led by half-time after Bugiel’s crisp finish was wrongly chalked off for offside having been played on by debutant Dara O’Shea.
The Dons created little, but were clinical, as Ipswich’s new-look defence was twice found wanting by Reeves’ in-swinging set-pieces from the right.
Ipswich improved after falling behind, driven by another new signing, Jack Clarke, with Huseyin Biler’s super challenge denying Al-Hamadi before substitute Massimo Luongo shaved the outside of the left-hand post.
The Ipswich boss brought on four of the side which started at the Etihad on Saturday and levelled when Chaplin bravely beat Dons keeper Goodman to a high ball, but the visitors ultimately failed to capitalise on the lifeline.
'Beating a Premier League team is outstanding'
AFC Wimbledon manager Johnnie Jackson told BBC Radio London:
"We said to the lads there will be no repercussions if it (the penalty shootout) doesn’t go our way, so hopefully that brought them a bit of calmness. They took them really well.
"It’s the highlight of my career, certainly one of them.
"That’s the third time coming up against Kieran as a manager and it hasn't gone great for me in the previous couple, so to win tonight against such a talented young coach is nice on a personal level.
"But I’m just really pleased for the football club to have a night like this. Beating a Premier League team is outstanding."
'It's really clear what our priorities are this season'
Ipswich Town head coach Kieran McKenna told BBC Radio Suffolk:
"There were some really positive things about the performance, there wasn’t too much wrong with it apart from our defending of two set-plays that we gave away cheaply.
"That put us in a difficult situation, and our slickness in the final third to create chances will improve as the understanding between the players develops.
"That wasn’t quite there, but other than that there wasn’t too much wrong with the performance.
(On making 10 changes): "I think it was the right thing to do. Of course, going out of a cup competition is not good, we’re disappointed for the supporters who have come here tonight and given us really good support.
"We wanted to progress in the competition, but it's really, really clear what our priorities are this season."
Player of the match
After the opportunity to rate players has closed, the score displayed represents the average from all the submissions by BBC Sport users.