Bellerin - who was drafted into the Spanish squad to replace the injured Dani Carvajal - has been able to give national coach Vincent del Bosque the lowdown on the well-known Czech pair.
Cech has just completed his maiden season with Arsenal, having joined from London rivals Chelsea in July 2015.
"Petr, for us at Arsenal, is one of the most immense pluses we could have had this season. He's got the Premier League record for clean sheets," Bellerin told UEFA.com.
"He makes you feel safer with him behind you. He'll be as important for the Czech Republic.
"He's perhaps the best goalie I've ever seen and he's helped me grow in experience by chatting to me and sharing things in Spanish."
Rosicky, meanwhile, has just been released from Arsenal after 10 years with the Premier League club.
Bellerin admits Spain cannot afford to allow the midfielder time and space to dictate proceedings at the Stade Municipal.
"Tomas is one of the most intelligent players around, but because of his injuries people underestimate him. But his intelligence, his ability to find space and his crossing definitely make him one of the players we have to fear," he added.
"Rosicky orchestrates the midfield and he's a great player who's quick on the ball and really clever, so we know we have to be very wary of him."