Jannik Vestergaard's stoppage-time header rescued a point for Southampton as they came from two goals down to draw 3-3 at Chelsea.
Timo Werner put Chelsea ahead on 15 minutes after a clever turn and run for his first Premier League goal.
The German got his second 13 minutes later, racing on to Jorginho's lofted pass and coolly lifting the ball over Alex McCarthy before heading in.
Against the run of play, Danny Ings halved the deficit as he rounded Kepa Arrizabalaga to tap in.
A defensive mix-up on 57 minutes allowed Southampton to equalise through Che Adams.
But two minutes later Werner found Kai Havertz who restored Chelsea's lead.
But in the second minute of added time, Theo Walcott's shot was glanced in by Vestergaard to lift Saints to 10th on seven points.
Chelsea rise to sixth on eight points.
Chelsea: 24 Oct v Man Utd (A)
Southampton: 25 Oct v Everton (H)
Referee: Peter Bankes. Assistants: Darren Cann, Mark Scholes. Fourth official: Martin Atkinson. VAR: Mike Dean. Assistant VAR: Peter Kirkup.