Courtois has developed a reputation as one of the finest goalkeepers in Europe over three years on loan at Atletico Madrid, winning La Liga and reaching the Champions League final last season.
But Cech, who has made 326 league appearances for the Blues over 10 years, is relishing the new challenge of retaining his status as Chelsea No.1 having been the undisputed first choice for much of his time so far in west London.
"I'm staying at Chelsea, that for sure," Cech told Ekipa24 after Chelsea's 2-1 win over Olimpija Ljubljana on Sunday.
"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."
Chelsea signed Courtois for €9 million (then £7.9m) from Genk in 2011, but he is yet to make his debut for the club having immediately been sent out on loan to Atletico.