Portugal coach Fernando Santos is confident Real Madrid star Cristiano Ronaldo won't be putting himself at risk facing Champions League opponents Manchester City.

Ronaldo feels confident he's overcome his thigh injury, despite warnings that he could aggravate it further if he plays against City.

"When I saw the play against Villarreal, when I saw him complain and leave the game, I was worried.

"We have already been informed of the situation and it is not so alarming. I think things will go well," said Santos.

"We will have, in all circumstances, a super motivated (for Portugal) Cristiano, but if he came with the great joy of winning the Champions League it would be even better."