Swansea, Wales: Chelsea scored four goals in the opening 36 minutes in its 5-0 demolition of Swansea in the Premier League on Saturday.
Oscar struck first within the first minute at the Liberty Stadium. Diego Costa added two more in the 20th and 34th, before Oscar grabbed a second for a 4-0 lead at halftime.
Substitute Andre Schuerrle made it 5-0 in the 79th, three minutes after replacing Willian.
Leader Chelsea has a provisional five-point lead over Manchester City which hosts Arsenal on Sunday. Swansea is ninth.
Jose Mourinho's side inflicted the worst home defeat in 24 years on Swansea, which sold top goalscorer Wilfried Bony to City midweek.
Gylfi Sigurdsson was dropped into a deeper role with Portuguese striker Nelson Oliveira handed his first start following his loan move from Benfica, but the formation did not seem to suit Sigurdsson as he gave away possession in the opening minute.
Oscar strode forward with purpose and lashed home a 20-yard shot which flew past Lukasz Fabianski in the Swansea goal and was officially timed at 49 seconds.
Sigurdsson almost equalized immediately with a 25-yarder which hit the outside of the post but the Chelsea midfield was running the show.
Fabianski saved from Eden Hazard before Chelsea cut through again with a move of stunning simplicity after 20 minutes, Willian and Oscar were involved before Cesc Fabregas slipped in Costa — the Spaniard's 15th league assist of the season.
Chelsea almost had another when Willian smashed against the post but the third goal arrived when Federico Fernandez's dreadful pass gave Costa the simplest of opportunities to tuck away his 17th league goal of the season.
Two minutes later and it was number four as Willian scampered through the middle to find Costa and his cut-back allowed Oscar to finish with ease.
Swansea attempted to inject some energy into its game at the start of the second half but Chelsea remained resolute at the back.
Chelsea went in search of a fifth goal and Hazard's 20-yard drive brought a fine full-length save from Fabianski before Oscar almost completed his hat trick from the same distance.
The visitors were not to be denied, however, and Schuerrle had the simplest task to tap Branislav Ivanovic's cross into an empty net 11 minutes from time and condemn Swansea to its biggest home defeat since a 6-1 loss to Wigan in April 1991.