Antonio Conte was frustrated Chelsea failed to kill off Sunderland, but lauded Thibaut Courtois for a stunning 93rd-minute save that ensured the Premier League leaders held on for a 1-0 victory.
Chelsea dominated at the Stadium of Light on Wednesday and led after 40 minutes through Cesc Fabregas, though Willian, Victor Moses and Diego Costa all failed to add to their tally.
Sunderland almost punished the visitors through Patrick van Aanholt, but Courtois leapt to his right to palm his swerving effort from the edge of the box wide.
"When you have the possibility to kill the game you must kill the game. We had this possibility but we didn't [kill the game] and at the end Courtois made a good save," said Conte.
"It was good. It is important for the future because today we didn't pay, but when you have the possibility to kill the game you must kill the game. I hope in the future we can improve."
Conte was pleased to see his decision to play Fabregas ahead of Nemanja Matic pay dividends as Chelsea moved six points clear at the Premier League summit with a 10th straight top-flight win.
He added: "Cesc is a good player for us. In the midfield I have four midfielders and it is important for me to evaluate the form of the single players, some games you need players [who are] more physical and some games with more technical [abilities]. It is important that Cesc had a good game.
"I prefer my players not to look at the table and to focus on the next game in three days. We must prepare very well to have a good Christmas."