An inexperienced Sharks side struggled to a 19-7 win over the Pumas in Witbank.
Coach John Plumtree hoped the match would offer him greater insight into the abilities of some of his fringe players but they struggled against a determined Pumas outfit.
The Sharks became more structured in the second half, but their early looseness allowed the hosts to stay in contention.
They are expected to field something close to their strongest side against the Bulls in their final warm-up match on Wednesday 4 February in Durban.
Sharks - Tries: Monty Dumond, Luzako Vulindlu, Len Olivier. Conversions: Dumond, Ruan Pienaar.
Pumas - Try: Valentine van Wyk. Conversion: Rudi Vogt.