The Senegalese disappointed on the weekend as Bucs lost 3-1 on penalties to Royal Leopards in the King's Super Cup in Swaziland.
Sarr also did not have the best of games in Pirates' 2-1 defeat to Zamalek in the CAF competition on July 11.
Tinkler, however, has faith the combative midfielder will reassert his value on the trip to Tunisia.
"Yeah, I think Issa Sarr didn't have his best game, truth be told. But sometimes that happens," Tinkler says.
"He has been fantastic for us throughout last season and sometimes you get those days. I had those days as a player and it was one of those days for him.
"I kept him out there hoping that it will change for him getting his confidence back. Unfortunately it didn't happen.
"We know his strength, he's got a strong character and he will bounce back for CS Sfaxien," concludes the former Bafana Bafana enforcer.