Indeed, Tottenham's 5-3 win over Mourinho's men on New Year's Day could have potentially dented confidence and derailed the west London side's season.
But they stability the Blues showed thereafter, which was developed in direct response to the White Hart Lane defeat, was the 'key moment' in their season, Mourinho says.
The Chelsea boss told reporters: "The key moment was the stability after losing at Spurs, everybody stuck together and we were very calm.
"What pleases me is winning the title, the way we did it and the consistency we've shown in difficult periods."
It's perhaps a shame for Tottenham fans to see how Chelsea respond to defeats such as their New Year's Day loss at the Lane, for it seems to be the exact opposite for Spurs.
Indeed, the north London side usually have little to show for big wins - especially against Arsenal.
Mauricio Pochettino's men went unbeaten against the Gunners this term but are once again going to finish below them in the Premier League table.
Tottenham's win over Chelsea, meanwhile, will always be remembered as a great day - but the fact Spurs then lost to the Blues in a final and still missed out on the top four may just taint that memory a little.