When Mount, who has played most of his career as an attacking midfielder, joined United from Chelsea for £55m in 2023, his ability to play in central midfield was cited as one of the attractions.
Although too much time in his first two seasons at Old Trafford was spent dealing with injuries, the 27-year-old was able to make a consistent impact last term.
While it is still early days in this pre-season, from the evidence of the opening two games, against Wrexham in Helsinki and an admittedly limited Rosenborg side in Trondheim, there are definite signs Mount and Santos could form a very productive partnership.
It is already clear Santos is happy sitting deep, taking the ball off defenders, spotting gaps in passing lanes and pressurising opponents.
That allows Mount – who won the last of his 36 England caps four years ago – to use his undoubted abilities on the ball, helps him to find space, and move United up the pitch. It is not something he is generally noted for, but Mount is also not scared to make a tackle.
“I’ve known Andre for a while,” said Mount. “I’ve watched him from afar, since he broke into the first team at Chelsea.
“He’s a really good player and reads the game very well.
“He’s a little bit more defensive, so it allows me to push on a little bit more and work off him.
“Defensively as well, we’re both players that want to get around it, put tackles in, win the ball back and be aggressive.
“I’ve really enjoyed it. It’s a position I’ve played for many years from a young age. It’s a position that I love and I see myself in.”
Although he is not a veteran in any sense, Mount has taken his responsibilities as a senior professional in this summer’s opening pre-season games extremely seriously.
He has spent time with the younger players, and it was noticeable before the Rosenborg match that he spent time with Shea Lacey, whose fine opener in a 5-0 win must have nudged him closer to a permanent place in Carrick’s squad.
Speaking to journalists in April, Mount, whose contract runs to 2028, looked ahead to a campaign that would include a return to the Champions League and what contribution he could make.
“Next season we have a lot more games, which is what you want at a big club,” he said at the time. “Having the pressure of performing and winning games is what we love as players. If it’s a start or coming off the bench, I’m ready.”
It is the kind of attitude managers adore.
Carrick showed exactly what he thinks about Mount by making him captain for a short time in the second half in Norway, after Harry Maguire had gone off at the break before the bulk of changes just after the hour mark.
“You have different types of leaders,” said Mount.
“You have ones that are very vocal, but I see myself as one who leads by example and never stops working.
“I’ve been captain previously, years ago, so I love the role.
“Especially with a lot of younger players on the pitch, and off it as well, being able to speak to them and make them feel comfortable, it’s something I really like.”
There is over five weeks yet before the transfer window closes and United will continue to be linked with big money signings.
But Mount is certainly making a strong case to show the club already has what it needs in midfield.