WATCH: Mourinho mocks Wenger over lost titles
The 23rd-minute strike meant the Spanish forward became the third Chelsea player to score 20 or more goals in a Premier League season on multiple occasions, joining Jimmy Floyd Hasselbaink and Didier Drogba in achieving the feat.
Costa scored 20 league goals in his maiden season with the Blues in 2014/15, before dropping down to 12 Premier League tallies as the Blues struggled in their title defence in 2015/16.
As Chelsea close in on a second Premier League crown in three seasons, the Spain international currently trails only Harry Kane (21) and Romelu Lukaku (24) in the Premier League Golden Boot race.
