The Dutch champions will tackle their French counterparts next week in this season's opening round of group fixtures, with Ibrahimovic the main focus against his former club.
However, Van Rhijn, 23, is confident of dealing with the Swedish international.
I'm absolutely not afraid of Zlatan," he told RTV Noord-Holland.
"I've stood toe-to-toe with top strikers before. He's not giving Ajax sleepless nights."
Ibrahimovic scored 41 times in all competitions last season.