London, Apr 26 (IANS): English Premier League (EPL) leaders Chelsea defeated Southampton 4-2 here to boost their advantage over second-place Tottenham Hotspur to seven points, though Spurs have a game in hand.

Chelsea energised by their 4-2 win over Spurs in last weekend's FA Cup semifinal, got two goals from Diego Costa, who had gone seven matches without scoring, reports Xinhua news agency.

Tuesday's contest marked a return to form for Chelsea after looking flat in their previous Premier League match, a 2-0 away loss to Manchester United.

Chelsea took a 1-0 lead just five minutes in, when Eden Hazard converted at the end of a play that began with a perfect long ball from Cesc Fabregas.

Despite conceding early, the Saints kept their composure and were rewarded in the 24th minute with an equaliser, delivered by Oriol Romeu when the Chelsea defense failed to clear the ball after goalkeeper Thibaut Coutois turned aside a shot from Gabbiadini.

The Southampton goal was followed by a spell of end-to-end play that saw chances for both sides.

But the decisive moment came in first-half stoppage time, courtesy of Blues captain Gary Cahill, who connected with a header amid a scramble in front of the Saints' goal to put the hosts up 2-1.

Costa broke his scoring drought in the 53rd minute, heading in a perfect cross by Fabregas - the Spaniard's 103rd Premier League assist - to widen the lead to 3-1.

A fine play by Hazard and Pedro led to Costa's second goal, in the final minute of regulation, while Ryan Bertrand managed to score for Southampton in stoppage time.