The following year he returned and won both titles at the South African junior meet, earning himself a place on the international team for the 2017 World U18 Championships in Athletics.
[1] He was among the favourites to win the 100 m event but was beaten by compatriot Tshenolo Lemao by 0.04 seconds.
[2] The pair again took the top two spots on the podium in the 200 m, with Mlenga winning to become the last world youth champion in the event (the championships was in its final iteration).
[3] His third and final medal of the tournament came in the mixed 4 × 400 metres relay where, alongside teammate Gontse Morake and 400 m hurdles champions Zeney van der Walt and Sokwakhana Zazini, he finished third in the rankings.
[6] Mlenga won the 2018 African Southern Region junior title in the 100 m,[7] but was subsequently disqualified, having failed a drug test for the anabolic steroid Stanozolol at a meeting earlier in March that year.