Naisarani said the Sharks were known for their big physical forwards.

"We'll need to work twice as hard and have each other's back."

Naisarani has already shown he is a leader when it comes to physicality.

"My mindset in every game is to be physical."

He led by example in the Rebels' first win of the season in their third round encounter with the NSW Waratahs on Friday - earning selection in the Super Rugby team of the week.

Naisarani said the breakthrough highlighted that Melbourne had not been physical enough in its opening two outings.

He said there was a better chemistry among the players and it had made all the difference.

The Rebels sit second to the ACT Brumbies on the Australian table ahead what will be their first clash with a South African team this season.

The Durban-based Sharks have two wins, having defeated the Blues and Highlanders, and the Ballarat visit is part of a four-week road trip for them.

They are coming off a heavy 38-22 loss to the Hurricanes in New Zealand.

The Sharks have two of their key players under a cloud after suffering concussion against the Hurricanes.

Head coach Sean Everitt said Boeta Chamberlain and Makazole were struggling with concussion.

"We'll have to check their concussion protocols to see where they stand."

On the plus side though, the Sharks will regain fly-half Curwin Bosch, who is rejoining the squad after spending time in South Africa owing to a family death.

"Having him back is a boost for the team," Everitt said.

Despite the loss and setbacks, Everitt is upbeat about the Australian leg of the Sharks' tour.

He said the skill and talent they showed all bode well for the coming weeks.

"There's a lot to look forward to. There were some really good phases and passages of play and we'll look at that for positivity."

The Rebels women's side plays the ACT Brumbies in a curtain raiser on Saturday.