Jose Mourinho felt Diego Costa's absence cost Chelsea in the 2-2 draw at Newcastle United.
The controversial striker was retrospectively handed a three-game ban earlier this week, having been deemed guilty of violent conduct in last Saturday's Premier League win over Arsenal.
Chelsea did not initially fare well without the Spain international at St James' Park as goals from Ayoze Perez and Georginio Wijnaldum put Newcastle 2-0 ahead.
Yet the champions roared back with two goals in the final 11 minutes, Ramires and Willian earning a share of the spoils.
Mourinho, though, felt the key moment came before the game kicked off.
He told Sky Sports: "Of course [we missed Costa]. I believe the decision cost us two points. It's not fair to say, but he's a very important player for us."
Mourinho, meanwhile, was left baffled by the disparity between Chelsea's first and second-half performances.
He added: "I have to try to understand why a team can play so bad in one half and so well in another one.
"The first half was really bad in everything. We were bad in every aspect of the game. There were too many bad individual performances. They did nothing to be winning, but they were.
"Then I moved the team around and they responded very well. We got a point. It's not what we wanted but it's not bad. We started eight points behind first and finished eight points behind."
