Saints had been under pressure the whole game by Chelsea, although they never gave up.
• Southampton 1-2 Chelsea - match report >>
• Southampton 1-2 Chelsea - as it happened >>
Saints contained them for the most part and took the lead through Long's effort at the end of the first half, but, in the final 15 minutes, it all fell apart for Ronald Koeman's side.
After 708 minutes without conceding Fraser Forster was finally beaten as Cesc Fabregas curled home.
Then, on 88 minutes, Branislav Ivanvic leapt highest, heading home the winner.
That ends a run of six games unbeaten for Saints. A lot to ponder.
Photographer Stuart Martin was at the match to bring us the pictures.
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