Matic re-joined Chelsea in January from Benfica, who he joined as a make weight in the deal which brought David Luiz to Stamford Bridge three years earlier.
Chelsea showed their faith in Mourinho's choice and had to swallow their pride to re-sign the Serbia midfielder, who teamed up with Luiz to great effect in Saturday's 6-0 defeat of Arsenal.
Matic broke up play and provided clinical passes, including for fellow January arrival Mohammed Salah to score his first Chelsea goal which completed the rout.
"It is difficult (for him) to lose the ball," Mourinho said.
"But at the same time he is not the kind of guy to play any square passes.
"He can do so and keep possession, but he can see the movement forward, look at the passing into space.
"He is very clean. He recovers a lot of balls in a clean way, he doesn't make fouls in dangerous positions.
"I like him a lot because of his stability. He is a very stable player for someone who is still so young, only 25."
The arrival of Matic for a reported fee of £21million - considerably more than his valuation when he left - was offset by the big-money departures of Kevin De Bruyne and Juan Mata.
Matic is ineligible in Europe, having represented Benfica already in the competition, so is limited to Premier League appearances, where his influence is already bearing fruit.
Chelsea scored twice in the opening seven minutes against the hapless Gunners and struck a third from the penalty spot after the visitors were reduced to 10 men.
Mourinho's critics suggest the Portuguese would usually have applied a 'handbrake' then, preserving the lead and shutting out the game.
Instead, the Blues went for the jugular, and Mourinho answered those who question his pragmatic approach with his biggest win as Chelsea boss in counterpart Arsene Wenger's 1,000th match in charge.
"I don't understand where it comes from," the former Inter Milan and Real Madrid boss added.
"If you say that my teams have a lot of clean-sheets, I say yes. But to have a lot of clean-sheets doesn't mean you are a defensive team.
"It means you defend well. My teams normally score goals.
"I have the record of goals in the Spanish League and Italian League.
"I have the record points tally in every league I was in.
"I had players winning golden boots and being top scorer in the country, even in Europe."
It all makes one wonder how Chelsea would be faring if they had a prolific goalscorer, something Mourinho hopes to add this summer.
He said: "If you can have that and add it to the good squad we have and the team we're building, it will be a plus and give us a chance to be stronger and win more matches."