AmaZulu suffered back-to-back losses in the CAF Champions League group stages following a 2-0 defeat to Raja Casablanca on Friday evening.
Two changes for Usuthu from their loss to ES Setif showed in Sandile Khumalo and Thabo Qalignge with Matarr Ceesay and Siphelele Mthembu dropped.
AmaZulu were behind on six minutes after Hamid Ahadad ran onto a ball in behind the defence and lobbed the on-rushing goalkeeper Veli Mothwa with ease.
However, Usuthu looked to draw level in the next seven minutes from a cleverly worked free-kick around the area which Augustine Mulenga obtained and worked the opposite goalkeeper.
The host suffered another set-back on the half-hour mark with Mulenga withdrawn after he sustained a knock and Bonginkosi Ntuli introduced.
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Raja were close to double their lead after three minutes through a powerful free-kick outside the area from Mohamed Nahiri, but Mothwa palmed onto the woodwork.
Usuthu applied an enthusiastic start following the second period, but had the Raja rear-guard on high alert and thus watched every move dealt with effectively.
This promising spell of play from Usuthu remained just over the opening sequence of the second stanza, as the Moroccan giants stayed tight and compact at the back.
As such, Raja increased their tally a little into the last ten minutes of the match after a defensive mix-up by Usuthu had Ilias Haddad note and tucked past Mothwa.
Usuthu could've had a response in the dying minute through a flying header from Mbongeni Gumede, but he was parried and saw the visitors to victory.
Confirmed line-ups:
AmaZulu: Mothwa, Gumede, Malepe, Khumalo, Xoki, Sikhakhane, Makhaula, Buchanan, Qalinge, Mulenga, Memela.
Subs: Amonome, Masilela, Mlambo, Ceesay, Ekstein, Maduna, Ntuli, Majok, Mthembu
Raja Casbalanca: Fakhr, Hadhoudi, Harkass, Haddad, Jbira, Nahiri, Boulahroudd, Zrida, Ngoma, Moitaouali, Ahadad