Diego Costa kept up his fine goalscoring form as the Chelsea striker hit a hat-trick to help his team beat Swansea City 4-2 in the Premier League this afternoon.

John Terry's own goal proved the difference between the sides for much of the first half, but the Spain international headed home a 45th-minute equaliser to ensure parity at the break.

Costa, whose four goals helped him to the Player of the Month award in August, kicked off September in similar fashion by scoring two more as Chelsea took a three-point lead at the top of the table.

With both sides boasting 100 per cent starts to the season, something had to give at Stamford Bridge and it was the hosts that made the early running.

However, Swansea, without a league win over the Blues since 1981, made inroads toward ending that 33-year hoodoo on 11 minutes when Terry diverted the ball past his own goalkeeper Thibaut Courtois from a Neil Taylor cross.

Garry Monk's side pressed for a second and came close to finding it when Wayne Routledge's curling effort beat Courtois, but his shot glided narrowly wide of the post.

Chelsea began to find their feet and could have levelled when Terry headed a Cesc Fabregas cross over the bar, before Lukasz Fabianski tipped away Andre Schurrle's free kick.

The pressure soon paid off, though, as Costa powered a header past Lukasz Fabianski on the stroke of half time, before firing the Blues ahead early in the second half.

The former Atletico Madrid hitman bagged his sixth in four Premier League outings on 56 minutes, thrashing into the roof of the net following Fabregas's cutback - a sixth assist this season for the Spaniard.

Unperturbed by falling behind, City continued as they did in the first half and Courtois had to be alert to palm away a Bafetimbi Gomis shot bound for goal.

It proved a decisive save as Costa then wrapped up his treble, latching on to a tame Ramires shot to poke past Fabianski.

Loic Remy replaced the hat-trick hero on 72 minutes and soon marked his debut with a goal, before Jonjo Shelvey reduced the arrears with what would soon prove a mere consolation for the visitors.