Charlie Austin's stoppage-time penalty for Southampton broke West Ham United hearts after they had recovered from being 2-0 and a man down, to lose 3-2 at St Mary's Stadium.
Southampton looked in control after Manolo Gabbiadini had scored their first home goal in six matches, Marko Arnautovic had been sent off for a late challenge on Jack Stephens and Dusan Tadic had converted a penalty.
But Javier Hernandez netted either side of half-time to draw the Hammers level, each time pouncing after Fraser Forster had made a save.
But Pablo Zabaleta's push on Maya Yoshida gave Southampton their second penalty of the match and substitute Austin made no mistake.
See: Southampton report | West Ham live blog