All eyes have been on Cristiano Ronaldo and Leo Messi at the 2018 World Cup.

They're both unbelievable footballers and have each won five Ballon d'Or awards thus far.

However, neither of them are yet to win a FIFA World Cup - and this summer in Russia could be their last opportunity.

Ronaldo and Messi have both entered their thirties and are unlikely to be the same force they are now in four years time.

The 33-year-old Portuguese forward has started the World Cup in excellent form, scoring four goals in their opening two games.

Meanwhile, Messi has struggled with Argentina and Jorge Sampaoli's side are on the brink of an embarrassing elimination at the first hurdle.

The debate over which player is the GOAT [Greatest of All-Time] appears likely to go on for years to come.

Shearer on Ronaldo v Messi

Speaking on BBC ahead of Portugal v Iran, Alan Shearer nailed the major difference between Ronaldo and Messi.

It's difficult to compare the sensational duo - but the Premier League's all-time leading goalscorer put it perfectly.

"Messi is an artist, Ronaldo is a machine," said Shearer on BBC Sport.

There can't be many who can argue with that.

Messi and Ronaldo are both an absolute joy to watch and it will be a sad day for football when they eventually hang up their boots.

The Brazilian Ronaldo - who won two Ballon d'Or awards himself - recently argued that Messi brings more magic to football.

"With his incredible attitude, with his incredible winning mentality, Cristiano Ronaldo is a unique player,” Ronaldo was quoted as telling Bild by Spanish newspaper Marca.

"But I admit that Lionel Messi brings even more magic to football.

"With his dribbling, his complete form of playing football and his ability to generate surprising situations in the attacks."

Argentina desperately need Messi at his magical best for their final group game against Nigeria on Tuesday night.

The 31-year-old is yet to find the back of the net at this summer's World Cup.

Messi reached the final in 2014 but suffered heartache against Germany, with Mario Gotze coming off the bench to score the winner in extra-time.

Would you rather have 'Messi the Artist' or 'Ronaldo the Machine' in your XI? Let us know what you think by leaving a comment below.