Tottenham claimed a slender 1-0 win at Burnley on Tuesday's (AEDT) thanks to Son's late decider, which was set up by Kane.
The England striker ran away from goal to meet a corner delivery and headed back in the opposite direction, with Son pouncing to nod into the net.
It was the ninth time this season the Spurs pair have combined for a Premier League goal, just one shy of a new club record for a single campaign.
Similarly, Kane and Son edged close to the all-time Premier League record of 36 combinations set by Frank Lampard and Didier Drogba, with the gap now just seven.
Mourinho believes the duo's friendship is key to that understanding.
"They were in a team that's different to this team, but they play together for quite a long time," Mourinho, whose side are up to fifth, told reporters.
"That gives immediately a good understanding between players. The way we are trying to play I believe goes in the direction of their qualities as well.
"They are enjoying it, they are very good friends, which I think is very important when you have top players in a team.
"It's very important that the personal relationship is very, very good. In the end there are no egos, it doesn't matter who scores, what matters is us, the team, the club.
"They are amazing, two fantastic players but today we were a team and we were a team suffering together after [the draw against] West Ham.
"I was happy with that. We felt the pain together and today we are enjoying it."
Kane, who has now set a new Premier League record of 13 goal involvements after six matches, commented after the match that he felt Spurs were capable of something "special", and while Mourinho was in agreement, he would not call his side title challengers.
"This is a kind of match with all the ingredients to lose points. It's a Monday night, empty stadium, cold night, rain, an opponent who defends well against the attacking power of a team like us.
"When you want very much to win matches, you can do something special. I want the team to go to every stadium home and away to win, Europa League, Premier League, it doesn't matter.
"This is something special I believe because it's a change of mentality, philosophy. [But] I will never consider ourselves title contenders. I assume that every match we play, it doesn’t matter where or versus who, I promise that every match I tell the players a draw is not the result we want.
"I don't have anything more to this to promise. We go to every match to win, but we need to ourselves very balanced."