League Two Grimsby Town reached the FA Cup quarter-finals for the first time in 84 years as two penalties either side of half-time stunned Premier League strugglers Southampton.
Gavan Holohan put the visitors ahead shortly before the interval after referee Thomas Bramall ruled Lyanco had blocked Josh Emmanuel's cross with his arm.
Southampton defender Duje Caleta-Car then caught Danilo Orsi with a flailing hand not long after the restart, allowing Holohan to convert his second spot-kick of the game.
Caleta-Car's close-range finish gave Saints hope and Theo Walcott had a late equaliser ruled out for offside as Grimsby held on to spark scenes of mass celebration among the 4,000 travelling Mariners fans, who can now look forward to a trip to Brighton in the last eight.