The French-Tunisian has become a real cult hero with Gers supporters since joining the Ibrox club after a successful trial during the summer.
The free spirit loves to attack whenever the opportunity arises and has now scored seven goals for the Light Blues during the 2013/14 campaign.
Mohsni capped his man-of-the-match-winning display with a late strike in the 3-0 SPFL League One victory against Ayr United at the weekend.
But the former Ipswich and Southend player's performances at the back have sometimes raised eyebrows among the Rangers support.
And even his manager Ally McCoist once joked that he would end up "in a straitjacket" after signing the mercurial talent in the close season.
But McCulloch, who has struck up a fine partnership with Mohsni in the heart of the Gers rearguard, believes his team-mate is a massively under-rated player.
And he has pointed to the nine clean sheets the 26-year-old has helped the Glasgow club to keep during the 2013/14 campaign as proof of how astute he is defensively.
"We have got a great understanding now," enthused McCulloch. "Yes, Bilel is really relaxed in his approach to the game. But he is fantastic to play next to.
"I think he is a much better footballer than he gets credit for. I think that is 16 clean sheets we have kept now and he has been involved in a lot of them. That is very positive.
"It is a real statement on how we are performing. It is working well at the moment. We are looking forward to every game we play in now.
"Plus, at the other end of the park, he has pitched in with a good few goals. I have got a couple myself. Long may it continue."
McCulloch finished last season as top scorer as Rangers completed Stage One of "The Journey" by romping to the Third Division title.
The 35-year-old just pipped Andy Little to that honour despite playing many games in defence and midfield as well as up front.
McCoist is hopeful of bringing in another forward during the January transfer window as Nicky Clark and Jon Daly are the only recognised strikers he has.
His skipper admitted he would be prepared to play in attack if need be in the weeks and months ahead despite his success at the back.
He said: "I think the manager knows I will play anywhere. I am not too fussed where I play.
"I am not vain enough to say: 'This is my position! I don't want to play anywhere else!'
"I suppose that is just the way I am. But that is the way it has got to be at the club just now."
Despite their extensive recruitment drive in the summer, Rangers have serious injury concerns at the moment.
Kyle Hutton broke a leg in an Under-20 game against Partick Thistle at Firhill two weeks ago to join Ricky Foster, Chris Hegarty, Little and Ross Perry on the sidelines.
However, McCulloch has been hugely impressed with how the youngsters who have come into the team have performed in recent weeks.
Sebastien Faure has come in at right-back and performed well and Fraser Aird has also done superbly in the last four games.
The teenage winger netted a fine solo goal in the 3-0 triumph over Ayr and will be difficult for his manager to leave out.
McCulloch said: "Seb is a good player. He can play at right-back, at centre-half and central midfield.
"He is still really young and he has done well since taking over from Ricky. He is good to play alongside in defence.
"I think Airdy has done fantastically, too, since he came back into the side in the game against Arbroath.
"It is important to us that guys who come into the team do well and help us to maintain our form. We have a big squad now and everyone will play their part during the season.
"Boys like that, guys who have not really featured, have to do well when they come in.
"When you have not been playing every week you have got to take that chance when it comes along. You have to be ready.
"But the players who have come in have done that. I think both Seb and Airdy have been tremendous.
"I think we have a host of players with first-team experience who can come in and are more than capable of doing a good job.
"Dean Shiels, for example, is available again now and is a great player for us to call on."
McCulloch is optimistic Rangers can extend their record-breaking winning run to 21 games in the league meeeting with Stenhousemuir at Ochilview on Saturday night - despite their injury problems.
He said: "We are on a good run at the moment and we are looking forward to every game we play. We are scoring goals and defending well.
"But it is important that we respect our opponents and treat every game that we play in seriously. It will be difficult for us to keep winning away from home especially.
"We want to keep this run going for as long as possible. The support has been fantastic for us once again this season and has enjoyed the winning run we have been on.
"But it is a long, hard season. Nobody at the club is taking anything for granted at all.
"We all know we have to work hard and play at our best every time we take to the field to get the result that is expected of us."