Will Ronaldo or Messi beat the odds?

But back to Messi and Ronaldo.

In addition to their fine 2017-18 seasons, both will enter the World Cup healthy and rested. Ronaldo missed Portugal's 0-0 draw against Belgium in Brussels on Saturday as Santos afforded his star an extended holiday after Real Madrid's Champions League final victory over Liverpool in Kiev.

"I won't bother Cristiano by calling him after a spell where he's put in so much effort and is tired," Santos told reporters. "I don't have to talk with Cristiano. Hopefully he can have a great holiday and he can come back in good condition. That's the important thing."

Messi has also been given special dispensation, having been rested several times by Barcelona coach Ernesto Valverde in the final weeks of the season, presumably with one eye on the World Cup.

Not surprisingly, both Messi and Ronaldo are publicly playing down their teams' chances in Russia.

"We are not favorites," Ronaldo said earlier this year. "We have to be honest and humble and understand that, theoretically, there are teams with stronger names, like Brazil, Spain, Germany, also Argentina."

When asked if a failure to win a World Cup would be a blot on his career, Ronaldo said: "Honestly, I don't think so. I achieved everything I dreamed of in football. If you ask me if I want to win the World Cup ... of course I do. But if I had to end my career right now, I would be very proud. I never thought my career would be so beautiful."

Messi, meanwhile, rates Brazil as the strongest team, but that hasn't stopped him from dreaming of being in the winner's circle in Moscow.

"It is a lifelong wish and every time that a World Cup approaches the dream becomes a little stronger," Messi said during an interview on Argentine television in April.

"The 2014 final was painful because we came so close. Winning a World Cup is what we all want."

Even with a motivated Ronaldo driving them on, the task looks beyond Portugal, given the team's advanced average age and lack of quality, especially in midfield. Realistically, it would do well just to reach the quarterfinals.

Argentina is a more formidable unit, especially with its vast attacking resources. However success depends largely on whether Sampaoli can find solutions to several dilemmas - like who will partner Manchester City's Nicolas Otamendi in central defense (Roma's Federico Fazio or Manchester United's Rojo?), who will start in goal (United's Sergio Romero or Chelsea's Willy Caballero?) and should he play an extra striker to compensate for his team's attacking midfield deficiencies.

But even if Sampaoli finds solutions for all these problems, he'll still need Messi to produce yet another individually sublime performance over the course of the tournament.

Xinhua