Two goals from Tomasz Radzinski gave Everton a hard-fought victory and kept their dreams of European football alive.
The visitors had taken the lead on the half-hour mark through free-scoring front man James Beattie.
The England striker notched up his 18th goal of the season with a fine effort from 15 yards.
Everton's defence were left standing as Beattie picked up a Fabrice Fernandes cross and with home keeper Richard Wright bearing down on him, he unleashed a shot.
Wright managed to get his hand on the ball but it was not enough to stop it finding the back of the net and giving Saints the lead.
But apart from the goal it was a dire first half. Both sides seemed to forget their lofty league positions and thoughts of playing in the UEFA Cup.
Instead they reverted to the recent relegation dogfight their fans are more used to.
Neither side wanted to keep hold of the ball preferring to present it to the opposition on a plate.
But for the second period Everton decided to play some real football.
They camped out in their opponents penalty box and peppered the goal with shots.
But the visitors stood solid at the back and the Toffees looked like they were going to end the day with the upper hand.
But manager David Moyes had a few aces up his sleeve.
With half an hour left on the clock he brought on Kevin Campbell and Thomas Gravesen and the big names proved their worth adding extra steel to the home side.
Bu the big change came five minutes later with the introduction of superstar youngster Wayne Rooney.
England's youngest ever player caused no end of trouble for the Saints. His tenacious running was a constant thorn in their side.
But the goal just would not come and as the home side thought it was not to be their day Rooney popped up with a glorious cross.
Radzinski was there to meet it in the box and rose up to head home the equaliser in the 84th minute.
Everton added even more determination to their game in a desperate search for a winning goal and in the 93rd minute with seconds on the clock, Radzinski fired in his second.
He beat one man, turned another and launched a wonderful shot into the back of the net.
It was a cruel blow for Southampton but no more than the home side deserved.