Fernando Torres spurned two golden chances to give his side the lead inside three minutes as Southampton started nervously but the hosts soon settled and carved out a number of openings of their own with Adam Lallana twice denied by last-ditch blocks.
Chelsea threw on Oscar and Willian in the second half with the former immediately involved when he picked up a booking for theatrically throwing himself to the floor inside the penalty area when staying on his feet would have surely yielded a goal.
The visitors took the lead on the hour when Oscar’s speculative effort struck the post with Torres reacting the fastest to nod home the rebound.
The two substitutes then combined for Chelsea’s second when Willian rifled home before Oscar sealed victory late on when he broke through the hosts’ offside trap and added a third via a slight deflection.
2’ – CHANCE: Torres ghosts in behind the Southampton defence. He tries to pick out a colleague but it rebounds back in his direction. Lashed across goal... No one turns it home. Bright start from Chelsea.
3’ – CHANCE: A mistake in the middle of the park allows Torres another chance to drive at the Southampton goal. He turns inside a couple of defenders and takes a pop. Fonte gets back to deflect it behind for a corner.
17’ – CHANCE: Schneiderlin pops it through a pair of open legs to Ramirez who taps it into the path of Lallana. The midfielder weaves through the penalty area and has a crack... Blocked. Wonderful interchange from the hosts.
28’ – CHANCE: Great burst of speed from Chambers down the right. He cuts it back to Lallana who is faced by a wall of seven blue shirts... The recently capped Englishman shifts it onto his favoured right foot... Smashed at Azpilicueta. Big chance.
54’ – BOLD SUBSTITUTIONS: It's proving a very difficult season for Mata as he's hauled off for Willian. The Spaniard doesn't look happy at all. Schurrle off too. Oscar comes on.
56’ – BOOKED FOR DIVING: Oscar is in! The Brazilian knocks it around Davis and hits the deck... Surely a penalty? No! Martin Atkinson marches over and issues Oscar a yellow card for his theatrical fall.
60’ – GOAL: Southampton 0-1 Chelsea. Oscar cuts onto his right foot and has a crack from distance which takes a deflection and strikes the post. Torres reacts the fastest and heads home from close range. Relief for Mourinho.
66’ – CHANCE: Clyne delivers a cross from the left which Terry inexplicably leaves. Lambert nips in and gets his to the ball but can only head straight at Cech.
71’ – GOAL: Southampton 0-2 Chelsea. Oscar dances on the edge of the Saints penalty area and draws in a couple of challenges before playing it across the face of goal. Willian latches onto the ball and lashes home. The substitutes combine!
82’ – GOAL: Southampton 0-3 Chelsea. Oscar gets in behind the Saints defence - which was caught horribly high up the pitch - and, with the help of a slight deflection, adds Chelsea's third.
Mauricio Pochettino has now lost more matches than he has won with Southampton in the Premier League – he has won 11, lost 12 and drawn 13.
Chelsea do the double over Southampton for the first time since the 2004/05 season. (Infostrada)
There have been three or more goals in the last seven meetings between these two in the Premier League. (Infostrada)
Will Juan Mata still be a Chelsea player when the transfer window slams shut? Normally the consummate professional, Mata’s face was a picture of disappointment as he was hauled off by Mourinho shortly after the break. He looks a shadow of his electric self, so is it time to hand in a transfer request and start afresh somewhere else?
MAN OF THE MATCH
Oscar (Chelsea): Injected life into Chelsea’s play and was the focal point of his side’s second-half assault on the Southampton goal.
Southampton: K Davis 6, Chambers 7, Fonte 6, Lovren 6, Shaw 6, Cork 6, Schneiderlin 6, S Davis 6, Lallana 6, Rodriguez 6, Ramirez 6… Subs: Clyne 6, Lambert 6, Ward-Prowse 6.
Chelsea: Cech 6, Azpilicueta 7, Cahill 6, Terry 6, Cole 6, Mikel 6, Ramires 6, Schurrle 6, Mata 6, Hazard 7, Torres 7… Subs: Oscar 8, Willian 7, Essien 6.
THE MATCH IN A TWEET