London: Diego Costa demonstrated his killer instinct with a hat-trick as Chelsea came from behind to extend their 100 per cent winning start to the English Premier League season with a 4-2 win over Swansea at Stamford Bridge.


Chelsea's Diego Costa celebrates after scoring his second goal against Swansea City in their EPL match at Stamford Bridge in London on Saturday. Costa scored thrice as Chelsea rallied from a goal down to win 4-2. Pic/Getty Images 

Swansea, like Chelsea, opened the season with three wins from three games, and early on the visitors looked more like title challengers than their lethargic hosts.