Chelsea kept pace with the leading pack in the Premier League as they moved into fourth place with an impressive win at Southampton.
The Blues took the lead when Eden Hazard capitalised on poor marking before cutting inside Steven Davis and powering a shot through the legs of keeper Fraser Forster.
Southampton had plenty of the ball but could not find a way through a well-drilled Chelsea, who looked the more threatening and went close when strikes from Hazard and Diego Costa were saved.
Costa, however, beat Forster at full stretch with a wonderful curled effort from 22 yards.Victory was Chelsea's fourth league win in a row - a feat they last achieved in April 2015 - and put them one point behind Manchester City, Arsenal and Liverpool.
Hazard getting back to his best
Eden Hazard was the 2014-15 Premier League player of the season during a campaign in which former Chelsea manager Jose Mourinho said the Belgian had outperformed Real Madrid forward Cristiano Ronaldo.Hazard struggled to maintain those heights as he struggled last season - managing just four goals and rarely showing the pace and trickery that had made him such a threat.This season is a different story. He has already scored five goals and looks like he has regained the confidence to tease and torment defenders.He showed skill and power with his goal at Southampton, scoring in three consecutive Premier League games for the first time, then provided the pass from which Costa added his side's second.