A brace from Ronaldo and a Sergio Ramos goal saw Madrid to a comfortable 3-0 win over APOEL at the Santiago Bernabeu on Wednesday.
Sidelined domestically due to suspension, Ronaldo's return was timely for Madrid, who have been held to back-to-back LaLiga draws.
Casemiro hailed the Portuguese star, while he backed Bale – who was again jeered by his own fans.
"Speaking of Cristiano is very easy, we know that he's the best in the world," the Brazilian said.
"We're happy having him back and he looks strong. With his ability we always want to have him available.
"You can see that Bale is working, he wants to score goals and he's fighting to always help Real Madrid."
Without Ronaldo, Madrid have already fallen four points behind rivals and leaders Barcelona in the league.
Casemiro said there was no reason to panic so early in the season, with Ronaldo serving the final match of his ban when Zinedine Zidane's side visit high-flying Real Sociedad on Sunday.
"There is no worry in the dressing room," he said.
"We have drawn two games and people start talking, but we are calm and we are working just the same.
"This is football. There are days when you draw, there are days when things don't go well.
"But we have achieved three important points for us [against APOEL], especially to gain confidence ahead of a difficult match we have against Real Sociedad on Sunday."