Phunya Sele Sele have the fourth best defence in the Premiership having conceded a mere 16 goals while notching up eight clean sheets.
Mathoho, who has featured in 17 matches for the Free Staters, has been integral to that defensive record, according to Larsen.
Mathoho's form has been so good that it has prompted the Celtic coach to back the 20-year-old defender, who stands at nearly two-metres tall, to break into the national team.
"He is growing in leaps and bounds and is really impressive, so much that soon he will get a national team call-up," Larsen told Sowetan.
"It shouldn't be long before he gets noticed by national team selectors.
He added: "It's not every day that you have a player of his calibre who's got it all - the height, strength and, most importantly, age on his side."