Captain Danny Batth and Donovan Wilson plundered goals as Wolves dumped last season's beaten finalists Southampton out of the Carabao Cup.
Championship outfit Wolves scalped their Premier League hosts 2-0 at St Mary's, humbling a strong Saints lineup fielded by boss Mauricio Pellegrino.
Southampton might have lost last term's League Cup final 3-2 to Manchester United, but fully deserved their second-round exit this time around.
Batth's facile second-half header should have proved enough insult for the lacklustre Saints, but then Wilson scuffed home his first senior goal in the dying minutes as Fraser Forster slipped.
Wolves manager Nuno Espirito Santo made a full 11 changes from the side that lost 2-1 to Cardiff in Championship action at Molineux at the weekend.
None of Saturday's starting XI even made Wolves' bench, but the visitors still prevailed -- even despite striker Nouha Dicko wasting a trio of fine first-half chances.
Pellegrino made six changes to the Saints side that edged out West Ham 3-2 on Saturday, but still fielded eight first-team regulars, and new recruit Jan Bednarek.
Saints ought to have strolled home, but instead lacked any pace, incision or guile.
Dicko missed three gilt-edged chances in the first quarter of an hour all on his own.
The striker first failed to bring down a defence-splitting ball, blasted wide when played in again and then bungled wide from point-blank range after Ivan Cavaleiro's low cross.
Saints needed half an hour to realise they ought to win this tie at a canter, with Jeremy Pied twice blasting wide.
Bednarek should have scored when failing to reach James Ward-Prowse's free kick with his head, but later drew a smart save from Will Norris.
The combination of inept finishing and circumspect build-up left a half-time stalemate inevitable.
The interval yielded no marked improvement, with Dusan Tadic's risible penalty claim reflective of a wholly underwhelming night.
Saints' malaise quickly turned to shock however, as captain Batth headed home unchallenged from Cavaleiro's corner.
Norris turned Sam McQueen's cross on to his own crossbar in a rare Saints attack boasting any purpose, but not even a raft of replacements could arrest the hosts' slump.
And Donovan killed the contest when scuffing home after Michal Zyro's smart through-ball, with the luckless Forster losing his footing at the vital moment.