Cristiano Ronaldo said he promised to "always be looking for more and more and more" after scoring another hat-trick in Portugal's World Cup qualifying rout of Luxembourg.

Ronaldo netted his 58th career hat-trick – his 10th for Portugal – as the Selecao eased past minnows Luxembourg 5-0 on Tuesday.

The five-time Ballon d'Or, 36, winner scored two penalties within five minutes early in the first half before completing the treble three minutes from the end of the match after Bruno Fernandes and Joao Palhinha had also found the back of the net.

Portugal are one point behind Group A leaders Serbia, though they have a game in hand, heading into next month's crucial showdown on the road to Qatar 2022.

Ronaldo – who extended his all-time men's international goals record to 115 – wrote via Instagram: "Another victory, another step towards our goal, another historic night in defence of our colours!

"Everything becomes easier when we play at home and in front of an audience that cares for us from the first to the last minute…

"I had promised that I would always be looking for more and more and more!

"It's in my DNA and in our DNA, we're never content, we never lower our arms and we always go."