The match started 30 minutes late due to inclement weather and was played on a difficult pitch that did not allow Sundowns to play their usual flowing football.
It is not a bad result in the greater scheme of things, but should Wiliete score in the return leg in Pretoria, Sundowns will need at least two goals.
There was not much going on in the attacking third for either side. Bryan León had an early chance he could not convert, while Teboho Mokoena had a free-kick saved.
Tashreeq Matthews tested the goalkeeper with a shot, after which Mokoena was forced to leave the field, which will be a major concern for coach Miguel Cardoso and national team boss Pitso Mosimane.
There was even less to enthuse over in the second period, with Matthews again testing the goalkeeper.
Sundowns host Wilete in the return fixture on Friday.
Meanwhile, Durban City claimed a 3-1 win over AS Port Louis from Mauritius in the CAF Confederation Cup, but should have been out of sight in the tie and will hope the goal they conceded does not come back to bite them.
New coach Eric Tinkler was not impressed with his side's wastefulness in the game, but they do at least travel for the second leg with a two-goal cushion.
Haashim Domingo, Gaston Sirino and a Tashreeq Morris penalty sealed the win for the KwaZulu-Natal side.