Early in March, with only 19 points to their name Leicester, in the words of their midfielder Marc Albrighton, were "dead and buried" but six wins from their last seven matches means their destiny is now in their own hands.
With two games left they are in 15th place, three points above Hull City who are just below the relegation trapdoor.
A decent goal difference means victory at fellow strugglers Sunderland next weekend would virtually complete one of the most unlikely escape acts ever seen in the Premier League era.
"We were dead and buried eight weeks ago and everyone pointed that out, so if we can pull this escape off it will go down as one of the greatest," Albrighton told the BBC.
A first-half brace by Riyad Mahrez bagged the points against Southampton, but manager Nigel Pearson warned that Leicester are still far from safe, especially as his players have expended so much energy in recent weeks.
"Our energy levels weren't what they have been today and I think that's understandable because the players have committed so much to give us this chance of staying (up)," he said.
"The run we've been on, it's taken a lot out of the players physically and mentally.
"But we always said we want to get to the last game of the season with it still in our own hands and that looks to be the case. But there has to be an element of realism about the situation and we haven't completed the job yet."
Only twice since the Premier League began in 1992 has the side bottom at Christmas avoided relegation.
Sunderland managed it last season and West Bromwich Albion, where Pearson was assistant to Bryan Robson, did it in 2005. (Reporting by Martyn Herman; Editing by Douglas Beattie)