Chelsea dropped points for the first time in the 2016-17 Premier League campaign after drawing 2-2 against Swansea City on Sunday, as Diego Costa struck twice to secure a point for the visitors.
The Spain striker opened the scoring before the Swans hit back with two goals in the space of three minutes thanks to Gylfi Sigurdsson and summer signing Leroy Fer.
Summer signings David Luiz and Marcos Alonso failed to make their Blues debuts off the bench at the Liberty Stadium, with manager Antonio Conte instead being forced to throw on attacking reinforcements after his side fell behind 2-1.