Albion under-21s were hailed as “a special group” by their beaten opponents as they went through to the last 16 of the Bristol Street Motors EFL Trophy.
The young Seagulls powered through 4-0 at MK Dons in the first knockout round with all the goals coming in the second half.
Samy Chouchane broke the deadlock with a penalty after a foul on Ruairi McConville.
Joe Knight added a second before the hosts had Dawson Devoy sent off.
McConville and substitute Sahil Bashir added late goals.
It was impressive stuff from the Seagulls, who have seen several players called in to the senior squad during their injury problems.
The side at MK included Josh Duffus, who went on as sub at AEK Athens in the Europa League last week.
Those Albion youngsters who walked out at stadium:mk would have been suitably inspired had they looked at the line-ups from a Trophy fixture between these clubs five years ago.
The Seagulls side which won 3-2 that night included current Arsenal defender Ben White, Sporting striker Viktor Gyokeres and Aaron Connolly, now at Hull City, who scored a hat-trick that night.
Chouchane, who has been in the senior Tunisia squad and travelled to Athens last week, drilled home the opening penalty and Albion took impressive charge from then.
Knight strode through and guided a low shot between the near post and goalkeeper Michael Kelly, who arguably should have done better.
Devoy was sent off after a foul as the last man when he lost possession just outside his own box The third goal was a storming individual effort by McConville, who charged through after more poor passing out from Kelly.
Bashir sent a low shot through Kelly to wrap things up.
Dons boss Mike Williamson added: “We've got to give Brighton some credit.
“They are a good team, a special group who have been together for a while, and they came here wanting to win the game.
“There are a few disappointing elements, but Brighton turned up with a real desire to win, to battle and to get into the next round. We want that from everyone in every game.”
Albion: McGill; Nilsson, McConville, Jackson, Slater, Mullins, Hinchy (Knight 46), Chouchane; Duffus (Bashir 90), Peart (Ifill 76), Flower (Gorman 76). Subs not used: Cahill, Atom, Tasker.
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