Chelsea’s No.1 showed his class with a flying stop deep into injury time to ensure Antonio Conte’s side made it 10 wins in a row.
Sunderland defender Patrick van Aanholt fired a drive toward the Belgian’s top corner but Courtois was at the top of his game to parry it wide.
“At half time I went out with the goalkeeper trainer”
And he has explained how extra training at half-time helped him to keep focused and warm after a quiet first 45.
He said: “I always try to stay 100 per cent concentrated.
“It was cold as well so at half time I went out with the goalkeeper trainer just to stay warm again.
“I think when it’s summer weather or not cold you can stay warm no problem.
“But when it’s cold like this it’s good to keep yourself warm so you can be busy with your hands.
“It proved to be good because early in the second half I made a good save and then in the last minute as well so it’s really good.”