Chelsea have conceded 50+ goals in a Premier League season (51) for the first time since 1996-97 when they conceded 55.
Diego Costa has been involved in 14 goals in his last 14 Premier League games for Chelsea (nine goals, five assists).
Chelsea interim boss Guus Hiddink was disappointed the Blues didn’t kill off the game against Sunderland as they lost 3-2 on Saturday.
Hiddink bemoaned Chelsea's missed chances as they were beaten by the Black Cats at the Stadium of Light.
Diego Costa broke the deadlock in the 14th minute before Whabi Khazri levelled for the homeside 27 minutes later with a cracking volley, but Nemanja Matic restored the lead for the Blues in the dying minute of the first half.
However, Fabio Borini and Jermaine Defoe handed Sunderland the vital win to move them out of the relegation zone as they scored in the second half before John Terry was sent off.
"It was an odd afternoon," Hiddink told Sky Sports. "We started very well and got the lead, but later on we didn't add to our advantage and invited them into it.
"We reacted well to make it 2-1 and in the second half we could have scored to make it 3-1, but we didn't. We invited them into the game and they did very well.
"We didn't score again and they still had the opportunity. For them it was must-win and I cannot blame the attitude of the team, we were a bit sloppy at times, but we came here to win and we didn't do so."
The highest Chelsea can finish in the league is ninth.
Jermain Defoe has scored 18 goals in all competitions this season, 13 more than any other Sunderland player.