Real Madrid travel to Lisbon for the fifth game of Group F knowing a point will be enough to see them progress to the knockout stages for a 21st season in a row.
For Ronaldo it is a fourth appearance against his former club since leaving for Manchester United in 2003, and he has scored in the previous three encounters.
And Navas expects his team-mate to once again shut out the emotions linked with a return to his boyhood club and fire Madrid to victory.
"For him it is a beautiful thing to return home," said the Costa Rica international.
"He has a great history [with Sporting], it is a special game.
"But he will always work with same intensity, the same enthusiasm. He will stay professional as he always does."
Navas goes into the game having kept back-to-back clean sheets in LaLiga but in Europe he has yet to stop an opponent scoring, something he is hopeful can happen in the Portuguese capital.
"I always have faith that the next game will be the one where we keep a clean sheet," he added.
"It has been difficult for us so far, we have been working hard and it is not just about the goalkeeper in keeping clean sheet. We all have to work hard defensively.
"But the most important thing is to get the win, and keep moving forwards."