Ronaldo's sister Katia Aveiro accuses Portugal fans of being forever ungrateful

Cristiano Ronaldo's sister, Katia Aveiro, has accused Portugal fans of being 'forever ungrateful' following criticism of her brother's performances, and has insisted that the Manchester United forward is still 'the best player in the world'.

Ronaldo endured a miserable evening on Tuesday as he squandered some key chances in Portugal's 1-0 defeat against Spain that saw his side miss out on the semi-finals of the Nations League.

Fans hit out at Ronaldo's display on social media, with some questioning whether he is still worthy of having a place in the starting line-up, but Aveiro has leapt to the defence of her sibling.

'He has his family and those who love him by his side. They will always be by his side, no matter what," Aveiro wrote about her brother on Instagram.

'But the current times don't surprise me at all. The Portuguese spit on the plate they eat [from], it has always been that way.

'That's why when someone appears from the ashes and changes mentalities, it bothers... With you always, my king. Calm down.'

Aveiro has admitted that Ronaldo is going through a tough period in his career, and has criticised supporters for not helping him when he is struggling.

Former Italy striker Antonio Cassano has also called for Ronaldo to retire following his quiet start to the season, but Aveiro believes her brother is still an elite player with plenty left to offer.

'It is necessary to give a hand to those who have always given theirs to Portugal. But the Portuguese are sick, petty, soulless, stupid, ungrateful and forever ungrateful. This guy who's sitting, he's on his knees... There's no one to give him a hand,' she continued.

'It is cruel. And it was already so much, but so much that he gave and gives. The one sitting is called Cristiano Ronaldo and he is just the best player in the world.'

Ronaldo is Portugal's all-time leading scorer with 117 goals, and he captained the side to Euro 2016 glory, plus won the first ever Nations League with his country three years later.

He continues to wear the captain's armband under Fernando Santos, and looks set to play a major role at the World Cup in Qatar despite the protestations of some supporters.