Cristiano Ronaldo scored twice and missed a penalty as Portugal survived a second-half scare against Latvia on Sunday.

The European champions had looked on course for a comfortable victory when the Real Madrid star converted a spot kick midway through the first half. 

However, after Ronaldo fired a second penalty against the post, Latvia hit back through a superb strike from Arturs Zjuzins.

The hosts responded immediately and retook the lead when William Carvalho headed in a Ricardo Quaresma cross. 

Ronaldo made up for his penalty miss by volleying in Portugal's third shortly before Bruno Alves rounded off the scoring with an injury-time header.

Victory in the Algarve keeps Fernando Santos' in touch with Switzerland at the top of Group B in World Cup qualifying.

GOALS:

At 27th min, Cristiano Ronaldo opened the scoring for the hosts with a first-half penalty.

Real Madrid striker hit the post with a second penalty after the break.

Arturs Zjuzins of Latvia levelled the scores with a fierce strike 20 minutes from time.

At 69th min, William Carvalho restored the hosts' advantage immediately with a header

At 94th min, Ronaldo added a fine volley before Bruno Alves rounded off the scoring.

In the closing moments, Bruno Alves helps himself to a back post header well into added time.