Ghanaian center back Mohammed Salisu climbed off from the bench for a rescue mission for his Southampton side who feared the worst when events leading to that 9-0 defeat to Liecester in 2019 repeated with a Jan Vestegaard red card in the 10th minute after a lunge on Jamie Vardy.
Southampton held Leicester to a draw despite playing more than 80 minutes with 10 men to frustrate the Foxes in their push to clinch a top-four finish.
Jannick Vestergaard was controversially sent off after just 10 minutes when his tackle on Jamie Vardy was deemed to have denied the Leicester striker a goal-scoring opportunity.
Vestergaard, on the edge of his box and the last defender, got the ball with a lunging tackle but referee Robert Jones deemed his follow-through on to Vardy's ankle had prevented the striker running in on goal.
That decision set the game's pattern, Leicester probing while Southampton defended deep, but it was the Saints who took the lead in the 61st minute.
James Ward-Prowse scored from the penalty spot after Kelechi Iheanacho had blocked Stuart Armstrong's effort with his arm raised up by his head.
Jonny Evans headed in Iheanacho's cross eight minutes later for the equaliser but under near-constant pressure Southampton's defence held firm.
Goalkeeper Alex McCarthy brilliantly denied Vardy with his right boot from close range in the final 10 minutes.
The point takes Leicester eight points clear of fifth-placed West Ham having played a game more but they have a difficult end of the season to come.
Mohammed Salisu has made just six starts with three substitute appearances since joining in the summer from Real Valladolid.