Jack Evans scored a 90th-minute winner against Southampton to move Blackburn Rovers four points clear at the top of Premier League 2 Division 2.
Saints, who would have gone level with Middlesbrough in the final play-off place with victory, thought they had held on for a draw when Jack Rose saved Joe Grayson's 84th-minute penalty.
But Southampton goalkeeper Rose was beaten when Evans curled in the decisive goal from the edge of the penalty area.
Blackburn will guarantee the Division 2 title and automatic promotion to Division 1 with three wins from their last four matches. They are four points clear of nearest rivals Aston Villa.
Saints are seventh, two places and three points outside the play-offs with two matches left.
See: Blackburn report | Southampton report
Next fixtures
Blackburn: 26 Mar v Wolves (A) PL2
Southampton: 13 Apr v Fulham (A) PL2
Evans' late winner for Blackburn
GOAL: #Rovers U23s 1-0 #SaintsFCU23s (Jack Evans 90)#SaintsFC concede late on as Evans curls an effort home from the edge of the area. pic.twitter.com/kzwhp7HqJn
— Southampton FC (@SouthamptonFC) March 20, 2018