The powerful Ivory Coast midfielder Toure emerged for the second half in a match that lacked any sort of realism due to the amount of changes made by both sides, but wound up hobbling up the tunnel with a leg knock on 84 minutes.
Fernandinho made his debut for the visitors with Vincent Kompany, Samir Nasri, Gareth Barry and Edin Dzeko also starting, but contributed little or nothing of note before being replaced at the outset of the second period.
Amid the rash of changes that spoiled the match from a competitive perspective , Toure, Joleon Lescott, Scott Sinclair and James Milner all emerged at the break, Cavin Johnson's side stuck to the plan a bit better.
Goals from Mame Niang on 56 minutes and a cool Kermit Erasmus effort with eight minutes left secured he South African Premier League side a surprise win.
Niang climbed above Matija Nastasic to head beyond Costel Pantilimon - who replaced England goalkeeper Joe Hart at half-time - from Edwin Gyimah's cross before Erasmus prodded the second goal into the net with Pantilimon left in no man's land.
City should probably have been ahead in the first half with Dzeko seeing a couple of efforts blocked by Ronwen Williams and Alexsandar Kolarov prodding a shot wide as he stumbled to the ground.
But Supersport were always a threat on the break as Chenen's cross was headed away by Kompany after eluding Hart in the City goal.
The team that finished sixth in their domestic league last term were rewarded for working tirelessly to close down space against their more revered opponents, who will surely not be too downhearted with over a month until the start of the Premier League campaign.
They must wait now to learn of the condition of Yaya Toure before their South African tour continues against Amazulu in Durban on Thursday.
- Sports & Recreation
- Yaya Toure
- Manuel Pellegrini
- Vincent Kompany
- Edin Dzeko
- Samir Nasri
- Gareth Barry