The match kicks off at 3pm on Sunday at Moruleng Stadium, Rustenburg.
Amajita coach Thabo Senong saw potential in Mabiliso at AmaZulu, prompting the call-up to the squad.
Mabiliso plays on the left-hand side of the defence and made an impression when he was with Platinum Stars, which led to AmaZulu signing him on a three-year deal.
The 19-year-old has already played 19 matches in all competitions for Usuthu, two of which were cup competition games, after having joined them in the middle of last season.
The Premier Soccer League recognised his promise and his efforts were recognised with a Young Player of the Season nomination, alongside SuperSport United’s Teboho Mokoena and the eventual winner, Maritzburg United’s Siphesihle Ndlovu.
Mabiliso said he and his teammates had a real understanding of what a win in this third and final round would mean for their individual young careers and the nation at large.
“It has always been a dream of mine to represent South Africa in the Fifa World Cup,” Mabiliso said. “Qualifying for this tournament gives us an opportunity to fight for that. And that’s why I’m planning to give it my all.
“I want to play abroad one day,” Mabiliso added.
“I don’t have any specific team in mind; however, the overall plan is to see myself playing there. The sooner that dream comes true, the better.
“We are playing Malawi here at home and that means we are the ones with the advantage in this first-leg encounter. We need to go out there and give it our all and make sure that we do not lose in any of those two matches.
“We really want to qualify for the 2019 Under-20 Afcon tournament.
“The team has been doing well and there’s no need to put ourselves under pressure. We just need to go out there and perform as we’ve been doing so far.”
– African News Agency