Portugal coach Fernando Santos is "absolutely sure" Cristiano Ronaldo will break his duck at Euro 2016 during Wednesday's decider against Hungary, as his side search for the three points needed to be certain of a place in the last 16.

The Real Madrid star had a frustrating night on Saturday when he missed a penalty and his side were held to a goalless draw by Austria in their second Group F fixture.

The Selecao das Quinas have scored a single goal so far in the tournament, recording a 1-1 draw in their opener against Iceland, and they could not add to their tally in their second match despite sending in 23 shots - six of those on target - as well as hitting the woodwork twice.

However, this is not something which worries Santos, who backed his misfiring striker as he told a press conference: "Ronaldo is a player who scores a lot of goals and I'm absolutely sure he will score in the next game against Hungary.

"It was the first time (against Austria) we failed to score under my reign.

"We created many chances, we didn't score, but I think we will next time. It doesn't matter if we play better or ugly football."

Santos is likely to lose both Andre Gomes and Raphael Guerreiro for the clash in Lyon as they sustained muscular injuries during the weekend stalemate.

Defender Bruno Alves insisted that, despite a delicate situation, everything was still in Portugal's hands.

"It's up to us to break them down. We need to believe and trust in ourselves, that we are able to beat them," he said.

Should they finish second, Portugal would face England in the last 16.

Hungary are currently top of the group and need just a point to progress but history points out that Bernd Storck's side have lost all five competitive games between the two nations to date.

Hungarian supporters were involved in disorders at Stade Velodrome in Marseille on Saturday, as they set off flares and clashed with stewards following the 88-minute leveller against Iceland.

UEFA have opened disciplinary proceedings over the chaos and will announce their sanction on Tuesday, making it yet another team to face punishment during Euro 2016.

Skipper Balazs Dzsudzsak urged the fans not to cause further troubles ahead of Wednesday night's clash in Lyon.

"I ask that everyone continues to support us, but in a way which does not give reason for any possible punishment," he said.

"Only the events on the field will determine how we finish the European Championship."