Scorers:S Long 42, C fabregas 75, B Ivanovic 89.
An Ivanovic bullet header a minute from time helped the blues to an important three points which moves the blues up to 11th in the league.
Both teams headed into this fixture with an unbeaten run to preserve. Southampton unbeaten in six, conceding no goals while the blues twelve domestic games without tasting defeat.
Hiddink was forced to make  an early change when Pedro had a hamstring problem in the sixth minute
Oscar came on as the hosts enjoyed the better of chances in the opening minutes. The blues settled and should have breached Forsters net with a rasping Oscar drive that was tamed by the keeper. The hosts were served the lead in the 42nd minute by a Baba rahman error allowing Shane Long to sprint to lob the ball past the onrushing Courtois.
Kenedy replaced Baba at halftime with the blues embracing an attacking approach in search for the equalizer.
Mikel headed just over following a corner that was not dealt with by the home side. Costa blasted wide in a swift counter attack involving Hazard and Fabregas.
The equalizer did arrive following a good effort from Costa who placed a pass at  Fabregas feet. The Spaniards intended cross for Eden hazard Eluded Forster and hit the back of the net. The hosts had Pelle and Sadio Mane brought on.
The blues pressed harder in search of the winner that did arrive as Ivanovic rose highest to meet Willians corner with a sublime header that secured an important three points.