Southampton had a big chance on 16 minutes when Adam Lallana found space inside the area, but his goal-bound shot was blocked by Ashley Cole on the penalty spot.

Torres sent a shot over the bar after a purposeful run from a wide left position got him inside the area on 20 minutes.

Southampton's English striker Jay Rodriguez controls the ball as Chelsea's English defender John Terry chases during the English Premier League football match between Southampton and Chelsea at St Mary's Stadium in Southampton, southern England, on Januar © Getty Images

Chelsea had Cole to thank once more when he got back to deny Jay Rodriguez after the striker was about to shoot after bringing down a lofted pass.

Cesar Azpilicueta was next to deny the Saints with a block inside the area just before the half-hour mark.

Andre Schurrle had an effort cleared off the line after Eden Hazard danced around a challenge to tee up his German teammate inside the area.

Chelsea wanted a penalty when Oscar went down under a challenge from Kelvin Davis in the Southampton, but the referee booked the Brazilian for a dive, with replays vindicating the official's decision.

Fernando Torres of Chelsea celebrates after scoring the opening goal during the Barclays Premier League match between Southampton and Chelsea at St Mary's Stadium on January 1, 2014 © Getty Images

Torres scored in fortuitous circumstances when he reacted quickest after Hazard's cross looped over goalkeeper Davis and bounced to the striker off the post on the hour mark.

Rickie Lambert spurned a glorious chance five minutes later when he crept in ahead of John Terry, but his header was tame.

Willian gave the Blues breathing space when he fired home an effort with 20 minutes remaining, before Oscar made the result secure with a left-footed finish after he escaped the offside trap.