Le Tissier, who had not trained much recently because of a calf injury, was held on the bench until 20 minutes from the end. Then the Southampton manager, Dave Jones, pitched him into the frenzied action which was threatening to go the distance without a goal.
With his second touch, Le Tissier conjured a goal. Carl Cort conceded a free-kick on the left and the Channel Islander curled the ball towards the far post where James Beattie rose to head firmly home. If that produced frenzy among the 10,000 travelling fans from the South Coast, the clincher with six minutes to go was pure genius and was received as such.
That right foot was in action again to bend a corner-kick from the left- hand side which ended up in the net. Hassan Kachloul seemed to get a deflecting touch but afterwards Le Tissier said: "Robbie Earle's head got a touch to the ball but it was going in anyway and I'm claiming it."
So salvation lies in Southampton's own hands, next Saturday at home against Everton. Dave Jones, an ex-Everton man, said: "It doesn't matter who it is as long as we win. I have always said all we wanted was to have the decision in our own hands and that is how it will be now. We have to win next week to stay up. It looks like it's down to us or Charlton."
Southampton could not have picked a better time to collect their second away win of the season (the other, crucially, was at Blackburn) as they aimed for their 22nd straight year in the top division. They could also, it has to be said, not have been pitted against more suitable opposition than Wimbledon, who have now won only one of their last 20 matches. The heart attack which laid the Dons manager Joe Kinnear low also seems to have affected his players. You can almost see the skidmarks on the grass where their season has come to a halt.
Last week's win over Leicester which lifted the escape hatch, persuaded a huge contingent to make the trip from the South Coast to cheer their team on and it was a vital contribution. "All I could hear was our supporters," said Jones, while Le Tissier called it "brilliant support which turned it more or less into a home game." That said, it took Southampton half an hour to assemble their act. In that time Wimbledon looked far from lethargic or uninterested as they swarmed around Paul Jones, who was back in the Saints goal after making a surprisingly quick recovery from back trouble.
Jones was in action with three minutes played, punching away an inswinging free-kick from Alan Kimble and then diving to his left to make a brilliant stop from Cort's shot. Next, Carl Leaburn headed narrowly wide before Jones's leg got in the way of a goal-bound effort from Earle at close range.
After 34 minutes Southampton woke up and seemed to have scored. Claus Lundekvam's header from a Chris Marsden corner was poked home by Marians Pahars, only for the offside flag to be raised. But Southampton had spotted a crucial flaw. "Wimbledon were not defending the post at corners," Jones said afterwards. That was to prove the match-decider.
Then Chris Perry spoiled a fine afternoon by overrunning the ball under a challenge from Pahars and it rolled free to David Hughes. With all the goal to aim at, he permitted Sullivan to make a blocking stop and understandably held his head in his hands.
Southampton had their own let-off three minutes before half-time. A Mark Kennedy cross gave Earle a free shot but Francis Benali stopped it on the line and bundled it clear. From then on Southampton seemed to know the match would end up theirs, and there was a cheer after 50 minutes when Le Tissier began to warm up.
It seemed Southampton might not have needed him as Beattie went close from Kachloul's cross and the Moroccan began to run free down the left, causing problems every time he got the ball. A sudden Kachloul shot seem to surprise Sullivan, who could not cling on to it. As the ball rolled tantalisingly close to goal, Beattie was just unable to force it home before the danger was smothered.
As an Andy Roberts shot skimmed the Southampton bar Le Tissier was brought on. "He hadn't wanted to start the game in case he broke down," said Jones. But as soon as he came on, the amazing "Le Tiss" turned the match conclusively Southampton's way. At the end the ecstatic Saints fans were chorusing: "We're staying up". It is beginning to look very much like it.