Swansea City goalkeeper Lukasz Fabianski has blamed himself for Chelsea's second goal at Stamford Bridge.
Fernando Llorente had levelled on the stroke of half-time after Cesc Fabregas had put Chelsea ahead.
Pedro's curling effort deceived Fabianksi to restore Chelsea's lead before Diego Costa sealed victory for the Premier League leaders.
"That's my mistake," Fabianski said of Pedro's goal.
"I should have caught it or pushed it away.
"It went underneath my body and it's a goal I'm at fault for.
"We are disappointed with the result because for long spells of the game we were in it.
"We had some chances, defended well, but the second goal basically killed the game for us and for me was very disappointing."
Chelsea's win stretched their lead at the top of the Premier League table to 11 points while Swansea are 15th and three points above the relegation zone.
Despite defeat at Stamford Bridge, Fabianski said Swansea could take encouragement from their performance against Antonio Conte's side.
"They're top of the league, going for the title and probably will be the champions so that's very encouraging especially playing away from home," the Poland international said.
"If it wasn't for the second goal who knows what could have happened.
"We should take all the positives from our performance."
'Massive month ahead for Swansea'
Swansea host Burnley at Liberty Stadium on Saturday, 4 March at the start of what Fabianski acknowledges is a big month in their battle to avoid relegation.
Burnley, a team Swansea beat on the opening day of the season, are seven points ahead of Paul Clement's side in 11th position.
Swansea then face three relegation rivals - Hull City, Bournemouth and Middlesbrough - in their next games.
"It's a massive month and we'll be playing against teams that are in and around us," said Fabianski.
"That will be very important especially after we've been through a difficult period when we played against really good teams.
"We have to do our best to get maximum points out of it.
"It will be a massive period for us and we have to focus on the Burnley game
"We'll be playing at home and everyone will be expecting us to get maximum points."