Cristiano Ronaldo has hit out at Iceland's "small mentality" after they claimed an unlikely point against Portugal in their European Championship debut on Tuesday.

Real Madrid superstar Ronaldo endured a frustrating evening in front of goal as he failed with several chances in his bid to become the first player to score at four consecutive Euros.

And his mood was not helped when Birkir Bjarnason's equaliser cancelled out Nani's opener to earn Iceland a famous point in their maiden appearance at a major championship.

The Portugal captain was less than impressed with what he perceived to be a negative style of football from Iceland, claiming they never attempted to win the Group F encounter, and also criticised their on-pitch celebrations.

"It was a little bit frustrating, we tried hard to win the game, Iceland didn't try anything," he said.

"They scored a goal, they created two chances in the ninety minutes and otherwise they got every player behind the ball, they put the bus in the net so it's difficult when one team don't try but Portugal try and play football and try to win the game.

"It's a bit frustrating for us but it's just the beginning for us, we're not worried about that. If you see Spain, France, they are the strongest teams in the tournament and had a difficult time to win their games so for us it was tough but we are confident. We're 100 per cent confident we'll win our next game.

"The rankings don't mean anything. We just try our best, keep the ball all the time and Iceland didn't try anything, they were just 'defend, defend, defend' and playing on the counter attack. 

"It was a lucky night for them. We should have three points but we are okay. I thought they'd won the Euros the way they celebrated at the end, it was unbelievable.

"When they don't try to play and just defend, defend, defend this in my opinion shows a small mentality and they are not going to do anything in the competition."