Portugal coach Fernando Santos said his decision to leave Cristiano Ronaldo out of his team for Tuesday's 6-1 triumph over Switzerland in the World Cup last 16 had been "strategic and nothing more."

Santos had expressed his unhappiness with Ronaldo's reaction to being suspended in the final group stage game against South Korea but he said that matter had no impact.

"I said that it was closed and it was closed. Cristiano Ronaldo is one of the best players in the world playing professionally and as a captain ... so we have to just think about this team collectively," he said.

Asked whether it was the most difficult decision of his career to leave out Ronaldo, Santos said: "I have a very close relationship I always have, known him since he was 19 at Sporting, and then for years here in the national squad," he said.

"Ronaldo and I never confuse the human and personal aspect with the coach and player relationship. He is a very important player to have in the team," he said.

Santos said he expected a "very difficult" game against Morocco in the quarter-finals but said his team were clearly in good form.

"If we can continue like this and improve some things then that is a good path," he added.