But it may also have a far more important knock-on effect when the new season kicks off.
The reunion between the United manager and his former Chelsea midfielder came at a hefty £40 million price tag - almost twice the fee The Blues paid Benfica for Matic six years ago.
But the potential impact Matic’s arrival could have on the form of world’s most expensive footballer Paul Pogba could see Mourinho’s latest piece of business have a far greater influence on his team.
Pogba’s return to United and the Premier League last season drew mixed reviews, with Mourinho leading the cheerleaders who claimed his form justified his status as the world’s most expensive player.
But, with Pogba all too often required to take up a defensive midfield role for Mourinho last season, it was frequently difficult to make the case that the young Frenchmen looked like an £89 million footballer.
When freed to use his power and pace more in the opposition half, Pogba threatened enough to suggest he should be more than capable of adding to the five league goals he scored last season, not least because he also struck the woodwork six times.
Ander Herrera, one of United’s most consistently impressive performers last season, could be another to benefit from Matic’s ability to provide cover for Mourinho’s back four.
Matic also offers Mourinho some added tactical flexibility for the new season, either playing as the solitary holding midfielder or, on occasion, operating alongside a team mate in a 4-2-3-1 formation.
Veteran Michael Carrick, too, adds to the depth Mourinho can call upon for that role.
The Serbian’s 6’4” stature also satisfies an apparently important Mourinho requirement as the United manager continues his tendency to recruit players who would look just as at home on a basketball court as a football field.
Pogba, Eric Bailly, last summer, and Romelu Lukaku and Victor Lindelof this, all tower way over 6-feet tall and will help make United a physically daunting opponent if nothing else this season.
There should be little excuse for a lack of results from set-pieces, at both ends of the field.
And in the short-term, Matic’s arrival this week will also serve the important function of appeasing Mourinho, who had grown increasingly vocal during the club’s tour of the United States about their failure to add the final two big-money signings he wanted to make this summer.
“I’m happy with my squad but I would like to have two more players,” said Mourinho last week. “A midfield player that would give me more balance, more options to the team.”
Matic certainly ticks that box, with Mourinho final target being an attacking player who can operate on either flank.
The man in question is Ivan Perisic, the £48 million-rated Inter Milan star whom the Italian club have so far insisted is not leaving.
Mourinho’s comments were taken as one of the manager’s trademark complaints, aimed in the direction of the club’s executive vice-chairman Ed Woodward.
And it was probably no coincidence that, within days of Mourinho’s statement, a deal for Matic was clinched.
United were reluctant to pay Chelsea’s £40 million asking price for a player who turns 29 on Tuesday.
But the fact that Mourinho delivered two trophies and Champions League football in his first season at Old Trafford has certainly strengthened his bargaining position with his employers.
Now, the pressure and focus will return to Woodward as he attempts to convince Inter to do business for Perisic, with the new Premier League season less than two weeks away.
