Rangers emerged victorious from Saturday's fourth-round clash at the Falkirk Stadium after Nicky Law and David Templeton struck late on in a 2-0 win.
But 18-year-old Bairns midfielder McGrandles told several newspapers at the weekend that he was more impressed by Aberdeen - who knocked Gary Holt's side out of the League Cup with a 5-0 thrashing earlier this year - than Ally McCoist's men.
However, Mohsni - speaking as he helped hand out 2,000 free tickets to local school children at Lorne Primary in Govan - said: "I'm not going to have an argument with some player. I think he was upset with the defeat. When you are upset, you say some rubbish stuff.
"Of course I can say to Celtic they won't win the cup, or I can say that to Aberdeen. But it doesn't matter. We will see what happens.
"It is up to us to show we can win the Scottish Cup."
Rangers followed up their cup success with a 6-1 thumping of League One rivals Forfar on Tuesday as they confirmed a 19th victory in a row - a new post-war club record.
But Mohsni insisted completing the league season without defeat is not the club's main priority.
"At Ibrox, we can beat anyone," he said. "It won't be easy but we have the upper hand because the other sides are not used to the big pitch and the big crowd.
"Motivation isn't an issue. We just need to concentrate. We want to win the league as quick as we can. We're not thinking about records, just winning the individual games.
"I didn't even know we had beat the record until the manager told us after the game. It's great because we're now part of the history of the club.
"It would be great to go the season unbeaten but that's not what we are concentrating on, only each game as it comes."
Nicky Clark struck four times against the Loons at Ibrox and Mohsni has backed the former Queen of the South striker to continue improving.
"Nicky scored four goals - I can only remember Messi with five beating that," said the Frenchman.
"He was on fire against Forfar. He deserved every one of his goals. He was working very hard up front and tried to hold up the ball.
"He can play at a higher level. He just needs more confidence because he's a young player and that will help him find the net more often. He's very quick and is a good finisher."
Meanwhile, the rebel group hoping to win a place on the Ibrox board has pleaded with shareholders to delay casting their votes for the club's forthcoming annual general meeting.
The group, led by Paul Murray and Malcolm Murray, hopes to secure four directorships when the meeting takes place on December 19 but plans to write to shareholders beforehand.
In a statement given to Press Association Sport, it says: "We intend to post a statement to all shareholders in the next few days. In the meantime we would urge all shareholders not to send in their voting forms until they have read our statement."