Chelsea have swept aside Swansea City in a classy first-half performance which has seen them surge into a 4-0 lead after 45 minutes at the Liberty Stadium.

Chelsea player Oscar shoots to score the opening goal during the Barclays Premier League match between Swansea City and Chelsea at Liberty Stadium on January 17, 2015 © Getty Images

Jose Mourinho's side made a dream start as Oscar lashed the ball home inside the opening 60 seconds after being gifted possession by Gylfi Sigurdsson.

The Icelandic international almost immediately made up for his mistake with a rasping drive from 30 yards, but it cannoned back off the crossbar with Petr Cech stranded.

Thereafter, Chelsea's dominance was there for all to see and Oscar almost added his second after 13 minutes, but Lukasz Fabianski parried the Brazilian's effort away. Willian should have diverted the rebound on target, but the winger could only blaze his effort over the bar.

Oscar then fizzed another strike wide before Eden Hazard was denied by Fabianski, but Diego Costa made it 2-0 in the 20th minute with a composed finish after latching on to Cesc Fabregas's through-ball.

Chelseas Brazilian-born Spanish striker Diego Costa celebrates scoring his team's second goal during the English Premier League football match between Swansea City and Chelsea at The Liberty Stadium in Swansea, south Wales, on January 17, 2015 © Getty Images

Chelsea continued to dominate proceedings after going two goals ahead, with Costa wasting a good chance on his left foot before Willian cracked the post with a powerful drive.

Costa was then gifted a goal by Federico Fernandez as the defender's short back pass fell straight to the striker, who kept his composure to beat a stranded Fabianski.

Less than a minute later, Oscar grabbed his second goal of the match with a curling effort from the edge of the box.

There was still time for Willian to rattle the woodwork for the second time in the half, with Chelsea all but extending their lead at the top of the league to five points.