This is a big reason why: Another day for Cristiano, another chance goes begging. 

Surely he's got to score?

Cristiano Ronaldo's head is bowed as the referee blows for half-time.

This is a case in point: Have another look as Nani hits the post and Joao Moutinho fires over from the rebound...

As 0-0s go, this one's a keeper. Just a few minutes to go before the break and we could have had what, three goals?

Had Cristiano Ronaldo turned up...

Image source, Reuters

Is Alaba going to shoot? He lines it up, and beautifully bends one towards the back stick with real power, and Vierinha has to contort himself into some kind of dangerous yoga position to boot the ball clear with Martin Harnik's head just inches away. Any connection and it's too close to miss. 

Thierry Henry
Former France international on BBC Radio 5 live

Every time Austria play quick and direct they find an opportunity. They don't have the quality of Portugal, so that is what they have to do.

Marko Arnautovic finds David Alaba running down the right, he's brought down just on the egde. The Austria fans wanted a penalty... 

Who's the yellow card for? Pepe. Dangerous position...

Image source, Reuters

Portugal have had 11 shots so far - three on target (in green), seven off target (in red) and one blocked, the most of any side in the opening 30 minutes of a match at Euro 2016 so far.

Image source, Opta

Ronaldo again... Just what has happened to the Real Madrid man? 

Awkward is the word for it as he looks to fashion a shot from a bouncing ball just inside the box. His effort trickles towards the keeper. The man could use a goal... 

Borussia Dortmund's new signing Raphael Guerreiro tries a clever free-kick, looking to play in Ricardo Quaresma down the right but David Alaba is smart to it and intercepts. 

Portugal back with it and Nani finds Cristiano Ronaldo with a cross from the right, but the roars as he rises to meet it with his head are tempered by the offside flag. Austria keeper Robert Almer palms it away for good measure.

Image source, Reuters

Paul Collins: Don't know if you lot are watching same game as me (or vs Hungary) but Alaba is dreadful. Anyone could look good at Bayern Munich 

Teesra: The latest Ronaldic failure is of course the fault of those beastly Austrians who are only in it for a draw. 

George Harrold: This Austrian defence is a mistake waiting to happen

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The Portuguese are getting closer but they'll need to do better if they want anything out of this game...

Take another look at the moment Cristiano fails to find the target.

Portugal (left) are getting more men further forward on average than Austria, who are having to hang back so far.

Image source, Opta

Paul Fletcher
BBC Sport at Parc des Princes in Paris

Very little so far from the temperamental but undoubtedly capable Austrian Marko Arnautovic.

The Stoke forward has hugged the left touchline but had very little opportunity to influence this game.

Increasing signs of frustration from Austria, who are slowly losing any semblance of control on this game.

Image source, Getty Images

Are frustrations bubbling a little?

Ricardo Quaresma flicks out a bit as Sebastian Prodl shepherds the ball out for a goal kick, and he's arguing with the ref too. In the book.

Image source, EPA

Played short to change the angle, delivered into the box and Nani rises to nod towards goal, the ball cannoning back off the left-hand post.

It's not clear yet but Joao Moutinho fires over as it falls to him and Austria survive. Again.

Portugal were topping out at almost 80% possession in that little spell of pressure. 

Austria have survived the worst of it with that Ronaldo chance. 

Here's David Alaba down the left with a chance to get a ball in the box but it's poor. 

Portugal win it back and counter at breakneck speed for another corner...

Martin Harnik gamely chases a rare pass, a scrap of a ball into the Portugal half, but there's mettle at the back to crowd him out. 

Portugal build again. But a fifth corner of the match is played too long for everyone, even the scurrying Ricardo Carvalho at the back stick. 

The key question so far: Just how did Cristiano Ronaldo miss?

Can it be? Cristiano Ronaldo misses another sitter. 

Raphael Guerreiro plays a lovely one-two down the left before squaring to the Real Madrid forward but, right in front of goal, with about 30,000 Portuguese fans ready to spring on their heels, he stabs it wide. For him, it's really wide.

Take another look at Portugal going close through Nani and then Joao Moutinho, Austria have Robert Almer to thank for keeping the score 0-0.