Courtois will return to the Blues after a successful two years with Atletico Madrid, where he carved out a reputation as one of the best keepers in world.
However, Cech has admitted that he won't be giving up the keeper's spot without a fight to the Belgium international.
"I'm staying at Chelsea, that for sure," Cech told Ekipa24. "I really don't mind that there are two great keepers at Chelsea. That motivates me ever more.
"You always have to fight if you want to be on great level. And there is not only Courtois and me, even Matej Delac is showing that he is great keeper."
Cech made 45 appearances for Chelsea in all competitions last season.