James Ward-Prowse earned the win with a sensational free-kick from 25 yards to keep the Saints two points ahead of Cardiff, who won at home to West Ham.
Two late goals in five minutes earned Southampton an incredible victory against Tottenham to remain clear of the Premier League bottom three.
The midfielder’s strike came after calamitous defending allowed Southampton to draw level via Yan Valery, who pounced on Danny Rose’s mistake.
Victory seemed unlikely after a poor first half dominated by Spurs who took the lead when Harry Kane scored his 200th career goal.
But the incredible turnaround earned Ralph Hasenhuttl’s team a second consecutive home win – the first time Southampton have achieved that since December 2016.
Tottenham, whose manager Mauricio Pochettino was in the stands as part of his two-match touchline ban, remain third after losing a third league game in four.
Manchester United can move level on points with Spurs should they beat Arsenal on Sunday.
Source: BBC News