Bruno Fernandes believes Cristiano Ronaldo is at his best when facing criticism and hopes his acrimonious departure from Manchester United will fuel him at the World Cup.

Ronaldo's mutually-agreed exit from Old Trafford was confirmed on Tuesday following the turmoil created by his interview with Piers Morgan, and he headed into Thursday night's World Cup opener for Portugal as a free agent.

He seized centre stage as only Ronaldo can, winning a penalty before getting up to take it himself and become the first player to score in five World Cup final tournaments.

Andre Ayew equalised for Ghana but quickfire goals from Joao Felix and Rafael Leao helped Portugal kick off their Qatar campaign with a 3-2 win.

For many players, entering such an important tournament with criticism ringing in their ears after a messy divorce from their club could destroy them, but Fernandes believes the opposite is true of Ronaldo.

"I think he likes to work under that criticism from everyone, so I pray all of you to keep doing that because he gets the best of himself when you guys do that," Fernandes said.

"I still share the space with him in the national team and the main thing for me is that Portugal does the best we can in the tournament because if we do it, Cristiano will be happy, I will be happy and everyone in Portugal will be happy for us."

Manchester City playmaker Bernardo Silva has no idea where Ronaldo's club career will take him next, but agreed when asked if the veteran was capable of staying in one Europe's 'Big Five' leagues.

"Yes I think so. But it depends on what he wants. I don't know what he wants for his life. He has to speak with his family and decide for himself, right?

"I support his decision (to leave United) in terms of, it's his decision. He's my team-mate in Portugal – if he's happy, we're happy.

"We are happy to know that we can still count on him – not just the goal but he worked a lot for the team."

Bruno Fernandes backs Cristiano Ronaldo to excel at World Cup