Mofokeng scored his side’s third goal in a 3-0 win over Sint-Truiden as they moved up to second in the Belgian league table.
It was a goal of some quality as he latched onto a pass from Mateo Biondić and arrowed a shot into the bottom corner from the edge of the box.
It was a first start for his new side following a move from Orlando Pirates, and his second goal after also netting against Westerlo. He has made six appearances in all competitions.
The win is part of a good start to the domestic season for Union, who have taken 10 points from a possible 12, scored 11 goals and conceded only one.
This was their second successive 3-0 win after they beat Anderlecht in the Brussels derby at the weekend, a game in which Mofokeng was a late substitute.
Bafana begin their 2027 AFCON qualification campaign with a home clash against Guinea and an away trip to neutral Egypt to face Eritrea later this month.