Southampton had looked good for the three points after coasting to a 3-0 lead at half-time, but some questionable substitutions from Harry Redknapp coupled with David Healy's introduction for Leeds saw their lead wiped out.
The home side took the lead on 27 minutes when a Nigel Quashie corner was headed back across the box by Michael Svensson and Marian Pahars was on hand to nod the ball home for his first goal since April 2004.
They added a second when Theo Walcott broke down the right-hand side past Matthew Kilgallon before picking out Quashie who finished well with a right-footed effort.
Leeds' only real response was a tame effort by Rob Hulse that was straight to Antti Niemi.
Saints then grabbed a third when Dan Harding handled a Matty Oakley header and Quashie stepped up to slam the ball home for his second of the game.
Redknapp then made three substitutions at half-time which seemed to throw Saints into disarray.
Leeds clawed their first back on 71 minutes as Gary Kelly's corner, Leeds' first of the game, was headed home by skipper Paul Butler.
Just six minutes later David Healy found himself in space at the far post and his cross was tapped in by Robbie Blake, who also scored against the Saints at Elland Road.
Five minutes later it got worse for Southampton when Healy himself got on the scoresheet. His chip into the box was handled by Danny Higginbotham and the Northern Ireland international stepped up to grab the equaliser from the spot-kick.
They completed their remarkable comeback just three minutes later when Hulse pulled the ball back for on-loan Manchester United midfielder Liam Miller to score his first goal for the club before diving into the ecstatic away support.
Nigel Quashie, Saints' captain, put in an acomplished midfield display, scoring two goals and certainly did not deserve to be on the losing side.