Cristiano Ronaldo trains with Portugal ahead of their winner-takes-all World Cup qualifying showdown with Switzerland

CRISTIANO RONALDO has been training with the Portugal squad ahead of their winner-takes-all World Cup qualifying showdown with Switzerland on Tuesday.

CR7 and Co sit three points behind the Swiss, who boast a 100 per cent record with nine wins out of nine, knowing a win would see them reach Russia.

Fernando Santos' Portugal have won eight of their nine clashes, only losing once - 2-0 to Switzerland in September 2016.

While the Portuguese may sit three points behind their World Cup rivals, they have a far superior goal difference at +26, compared to Switzerland's +18.

That means a win of any margin would be enough for Portugal to qualify for next summer's tournament in Russia automatically.

Should they lose, they will still finish second and go into a the playoff scenario.

Portugal have scored 30 times, conceding just four, in qualifying so far - in no small part thanks to their talisman Ronaldo.

The Real Madrid superstar has scored 15 times - the second-highest tally in all of Europe behind Robert Lewandowski (16) - while adding three assists.

In fact, CR7 can boast a phenomenal goal every 45 minutes of Portugal's qualifying campaign so far.

With Portugal playing at home, they'll be leaning on him for some magic at the Estadio da Luz in Lisbon.

Ronaldo and Co most recently kept their World Cup dream alive with a 2-0 win away to Andorra on Saturday.

The former Manchester United star settled Portugal's nerves in the 63rd-minute to give the visitors the lead, before Valente Silva sealed the game in the 86th-minute.

Portugal will be relieved to have got over the line, having dominated the game, with a whopping 80 per cent of possession, while taking 20 shots to Andorra's one.