Bounou was initially selected to start against the Red Devils, but just seconds before kick-off, after the national anthems had been sung, the Sevilla man requested to be replaced as he felt nauseous.
That potentially could have been a huge miss for Morocco, as Bounou won the Zamora Award (best goalkeeper) and African MVP in La Liga last season.
However, his replacement Munir, while not overly tested by a poor Belgium side, was solid, and helped his side to a clean sheet.
Should Bounou recover in time though, there is no doubt he will come back into the side for this clash.
Regragui named an entirely unchanged side to begin with before Bounou's late withdrawal, and after another excellent display, it is likely that he will start with the same 10 outfield players again.
Noussair Mazraoui recovered from a slight injury which ended his day against Croatia early to feature from the start again against Belgium, and the Bayern Munich defender should start at full-back, with the fleet-footed Achraf Hakimi on the other side.
Leaving out of a significant number of known European-based stars has ended up being a masterstroke from Regragui, as there was some surprise when the likes of Munir El Haddadi, Younes Belhanda, Adel Taarabt, Faycal Fajr and the Mmaee brothers were all left out.
Five of the starters from a 3-0 defeat to the USA earlier on this year were all left out, while the likes of Adam Masina, Tarik Tissoudali and Amine Harit missed out with injury.
Morocco possible starting lineup:
Bounou; Hakimi, Aguerd, Saiss, Mazraoui; Amrabat, Ounahi, Amallah; Ziyech, En-Nesyri, Boufal