Chelsea’s Eden Hazard vies for the ball with Southampton’s James Ward-Prowse at Stamford Bridge on Sunday. (Source: AP)

Chelsea opened up a six-point lead at the top of the Premier League despite being held to a 1-1 draw against top-four hopefuls Southampton in an absorbing game at Stamford Bridge on Sunday.

Diego Costa opened the scoring for Chelsea in the 11th minute with a close-range header but Southampton deservedly equalised eight minutes later through Dusan Tadic’s fortuitous penalty.

Southampton dominated for much of the opening period but Chelsea asserted their authority after the break with Costa clipping the post while John Terry was denied in a frantic finish.

Chelsea lead second-placed Manchester City, who were beaten 1-0 by struggling Burnley on Saturday, with a game in hand while Southampton are sixth, three points behind fourth-placed Manchester United.

United host fellow Champions League qualification hopefuls Tottenham Hotspur and Newcastle United travel to Everton later on Sunday.