The Uruguayan midfielder has made a seamless transition to his life in a new country and continent.
Sirino has been with the Brazilians for just over a month, but the way he has clicked with his teammates it seems like he has been there for years.
Sundowns will unleash the tricky midfielder on their neighbours SuperSport United tonight in the Tshwane Derby at Lucas Moripe Stadium (6pm kick-off).
“We are fortunate because we did a lot of work on him before he came here,” Mngqithi said.
“We know exactly what he is capable of. To be honest with you, he hasn’t even given us half of what we think he can give us because he scores a lot of goals.
“He is very good in one-versus-one situations but he isn’t yet confident to go through and be more assertive in his game.
“We believe that what he has given us so far is enough because we know that with time he will give us more.
“It is encouraging for him and for a South American to come here and play like the way he has been playing in his first few matches.
“There are still some areas of his game that must improve, especially his play off the ball defensively. He is working and trying to improve that.
“The good thing is that he is very professional and is trying to give us the best he can.”
While Sirino’s transition has been seamless, the same cannot be said for Jeremy Brockie.
During his time with Matsatsantsa a Pitori, the New Zealand forward has struggled to break his goal drought that stretches all the way back to September.
Tonight’s match is a perfect platform for Brockie to open his Sundowns account, but he won’t have it easy against players who know him well.
Doubts have started to creep into the Kiwi forward who is now desperate to find the back of the net after 14 league matches without a goal.
What has made accepting the drought easier at Sundowns is that he doesn’t carry the burden of being the team’s only source of goals.
Almost everyone scores for the 'Brazilians' who have the most potent attack in the league.
Sundowns have dominated clashes against SuperSport, unbeaten in their last 13 matches in all competitions with 10 of those being wins.
“I don’t even think that what Brockie is going through is a struggle,” Mngqithi said.
“It’s our expectations. Under normal circumstances, a striker of Brockie’s quality is someone you would expect that if he doesn’t score in his first three to four matches, you’re still definitely sure that he is still going to score goals.
“The unfortunate part is that it is now beginning to get into his nerves.
“We are trying very hard to make him calm down and understand that we believe in him and we know what he is capable of.
“The unfortunate part is what we can’t control, because his intrinsic motivation and his anxiety to make sure that he does what we know of him is beginning to creep in and make him do things that are uncharacteristic of him.
“But we are still very confident about him.
“He is a very good player. We know what he can give us. I think that he is improving. He is doing much better game by game and it is a matter of time before he starts scoring.”