Olivier Giroud and Eden Hazard saw Chelsea complete a remarkable comeback from two goals down against Southampton to achieve a 15-year first for the club.
After their recent slip-ups against Tottenham and West Ham, many thought the Blues were down and out when Jan Bednarek added to Dusan Tadic's early opener at St Mary's to give the struggling hosts a comfortable lead at the hour mark.
With pressure building on coach Antonio Conte, the Blues looked set to see their hopes of a top-four finish in the Premier League disappear, but substitute Giroud emerged to pull one back in the 70th minute and keep them in the game.