“If Ronaldo has to play on his own against Uruguay, then Portugal will lose," Santos said.

"I hope that my team will play with the utmost concentration. We have a serious match ahead of us, and we will have to give our best throughout the game. If we can do all that, then Ronaldo has the ability to play the decisive role."

Portugal and Uruguay will play in the first match of the round of 16 in Sochi on Sunday (4am AEST).