Rickie Lambert's 35th-minute free-kick proved enough to seal a 2-1 win at St Mary's after an early opener from Jay Rodriguez had been cancelled out by a header from John Terry.
Chelsea's shock loss allowed Tottenham to leapfrog into third place with a 2-1 win at Swansea.
More top news
Wednesday morning's weather for the east of the region
Wednesday morning's weather for the west of the region
Tuesday night's weather for the west of the region