Mosimane confirmed his shock resignation as Sundowns coach on Wednesday after two weeks of talks with the Egyptian Premier League champions, where he will now sign a two-year deal on Thursday.
This website understands that negotiations took place via a five-hour Zoom meeting on Sunday, when the deal was struck with the understanding that he will be able to bring in his own backroom staff and possibly Sirino.
Having been rebuffed in their attempts to lure the 29-year-old to Cairo in April after club president Mohamed 'Bibo' El Khatib was left starstruck by his abilities in the CAF Champions League, a second bid will now be launched imminently.
However, Sundowns have made their stance clear that Sirino is not for sale and are said to have sarcastically quoted the Club of the Century a $50-million asking price due to the five-year deal the Uruguayan signed in June.
Despite Ahly holding an annual budget of $140-million, their transfer policy has taken a methodical approach to signings as they look to recoup investments by opting to sell players to the Gulf region and Europe.
Aubrey Modiba - SuperSport United boss Stan Matthews has confirmed that the versatile left-sided player's move to Sundowns is done.
Luvuyo Phewa - This signing went under the radar, but Real Kings confirmed a deal with Sundowns for the former SA under-20 star. He has since been loaned to Chippa United.
Lesedi Kapinga - Black Leopards' most exciting player this year signed a pre-contract with Sundowns in January and was allowed to leave before the resumption of the 2019/20 season.
George Maluleka - 'Mido' signed a pre-contract with Mamelodi Sundowns in January and was then sidelined him from the team and allowed to leave for Chloorkop during lockdown.
Gift Motupa - Sundowns finally landed their long-time target during lockdown after missing out in past transfer windows.
Mothobi Mvala - The former SA under-23 star's move is a surprise considering the sheer volume of midfielders at Chloorkop. A quality signing Sundowns just could not pass up.
Peter Shalulile - The 16-goal Namibian striker has expressed his excitement about the move after Highlands Park was sold to Tim Sukazi.
Kermit Erasmus - Unveiled by Mamelodi Sundowns on a three-year deal.
Khuliso Mudau - The right-back has signed a five-year deal with Sundowns.
Haashim Domingo - The exciting Ajax Cape Town youth product was the second ex-Wits star to confirm to KickOff.com that he had joined Sundowns.
Grant Margeman - SA under-23 international midfielder Margeman was signed in 2019 and then sent to Ajax Cape Town for the 2019/20 season.
Jody February - February was signed from Ajax Cape Town in 2019 and then loaned to Cape Umoya United for the 2019/20 season.
Ricardo Goss - The goalkeeper was the first of three former Bidvest Wits players to indicate to this website that Sundowns had signed him.
Brian Onyango - The 26-year-old Kenyan defender was snapped up on a three-year deal after initially being unveiled by TTM.
Rushine De Reuck - The 25-year-old has been signed from Maritzburg United on a five-year deal.
With one of their other targets in the form of Algeria playmaker Youcef Bellaili confirming he's likely to return to Europe, the Mosimane deal, as well as the potential arrival of Sirino, became imperative for the club's hierarchy.
However, it remains to be seen whether they're willing to invest heavily in Sirino at his current age, with little resale value on offer.
Sirino developed into one of Mosimane's main attacking outlets since his arrival from Bolivar in January 2018 with 24 goals and 29 assists in 99 games in all competitions.