The fiery Tunisia international was shown a straight red card by English referee Mark Heywood after aiming a flying head-butt at County striker Chris Martin towards the end of their 2-0 defeat at the IPro Stadium.
Heywood has now lodged his match report with Hampden chiefs, confirming the 27-year-old was sent off for violent conduct.
Under SFA sanctions, that offence carries an automatic two-match suspension and Mohsni will now sit out Tuesday night's Petrofac Training Cup first-round clash with Hibernian.
He will also miss the Ibrox side's Scottish Championship opener with Hearts on Sunday.
It is understood Rangers will not be able to challenge the ban as the deadline for an appeal has already passed.
But Light Blues boss Ally McCoist has already admitted Mohsni's actions were "indefensible".
Now the manager has warned the player his wild temper is stopping him from fulfilling his potential.
"He has apologised because he knows he let himself down and let his team-mates down," said McCoist. "We can't afford needless red cards.
"There is a package that comes with someone like Bilel but we want to cut out the silly stuff. If he can do that, then it would be to the benefit of everyone at the club.
"I have had a very good chat with him and what I can say publicly is that he 100 per cent knows he was wrong. We can't accept that that type of behaviour at the football club.
"That hot-headed streak certainly does not help him as a player. If he could cut that out of his make-up it would make him a better all-round player."
Meanwhile, McCoist admits he is keeping his fingers crossed that the club's off-field woes will become a thing of the past.
The Ibrox club have endured a turbulent two-year spell since rising from the ashes of liquidation.
The club burned through almost £70million in the first 18 months of that period and infuriated supporters have even gone as far as to organise a boycott of season-tickets while calling for assurances over the future of the stadium and the Murray Park training ground.
But on the eve of his side's first match of the new season McCoist claims once stormy seas have calmed, he is hopeful he will be finally allowed to concentrate on football matters.
He said: "It would be great [if all I had to concentrate on was football matters]. It would be ideal.
"I have to say that I think things have absolutely calmed down. There are obviously one or two things that happen in all clubs that are for board members to deal with.
"That's not my gig, I'm manager of the football club and hopefully I can concentrate on the football issues.
"Certainly I think we can all agree that there are still issues. That's fine, all clubs have issues. But we are in a far calmer and far better place."
McCoist has opted to take a backward step from the numerous rows that have dominated Rangers' dealings over the past six months.
And he hinted he would stick by that no-comment policy ahead of the new season.
He added: "I'm very, very hopeful that the team can put the club on the back pages for the right reasons.
"Off the field issues I can't have any bearing on. We have got enough problems picking sides to win games of football before we can start worrying about anything else."
McCoist has added four new signings to his squad this summer after luring strikers Kris Boyd and Kenny Miller back to Govan, as well as capturing defenders Darren McGregor and Marius Zaliukas.
But he has not given up hope of landing further new faces.
He said: "I'm happy with where we are. Like every other manager, you would always want a wee tweak with your squad.
"You never know, if I get the opportunity to add to my squad I will certainly do that. There is still a long time to go in the window."