MOSCOW, June 5 (Xinhua) -- Lionel Messi and Cristiano Ronaldo have won nine UEFA Champions League medals, 11 La Liga titles, three English Premier League crowns and a raft of other domestic and continental trophies.

On an individual level, they are the all-time top scorers for their respective national teams and have each won five Ballon d'Or awards. But there is one piece of silverware that Ronaldo and Messi are yet to win. And it just so happens to be the most coveted prize in world football.

That could change within the next six weeks in Russia as these giants of the modern game embark on what will perhaps be their last shot at World Cup glory. Ronaldo will be 37 by the time the next World Cup comes around in Qatar while Messi, despite being two years younger than his rival, has indicated that this might be his last appearance at football's showpiece event.

As far as individual form goes, both are coming off impressive seasons for their clubs, even if they weren't quite as prolific as in previous seasons.

Ronaldo scored 42 times in 41 matches across all competitions for Real Madrid in 2017-18, including 15 goals in the team's triumphant Champions League campaign. Messi scored 45 times in 54 games for Barcelona, helping the Catalan side to the La Liga-Spanish Cup double.

Their preeminence as the world's best players now stretches beyond a decade and is showing no signs of fading. But will the pair's own individual brilliance be enough to take their respective teams to football's summit in Russia?

Real Madrid's Cristiano Ronaldo celebrates after winning the Champions League at NSC Olympic Stadium, Kiev, Ukraine, May 26, 2018. [Photo: China Daily/Agencies]

While Portugal are reigning European champions and Argentina were runners-up in each of their past three major tournaments (the 2014 World Cup, the 2015 Copa America and 2016 Copa America), both teams are arguably in decline.

The Iberians, in particular, seem to be over reliant on veterans who are beyond their prime. The backline will be led by 35-year-old former Real Madrid enforcer Pepe, who is likely to be partnered in the center of defense by either Bruno Alves, 36, or Jose Fonte, 34.

The team also lacks a creative playmaker, with 34-year-old Ricardo Quaresma perhaps their best option, despite being used mainly off the bench in recent years. On the positive side for the Selecao das Quinas, they have shown that their fortunes do not hinge entirely on Ronaldo.

Portugal's 1-0 triumph over France in the 2016 European Championship final was largely achieved without their No. 7, who was forced to leave the Stade de France pitch after 25 minutes due to an injury.

Current form also suggests that Portugal will be difficult to beat. Fernando Santos' team qualified for the Word Cup by losing just one of their European qualifiers. Ronaldo and Andre Silva formed a formidable attacking partnership with 24 goals between them. In addition, Santos has instilled great unity and self-confidence in his squad, qualities that have been ever-present since the glorious summer of 2016.

Lionel Messi celebrates scoring Barcelona's third goal during Sunday's 4-2 league title-clinching victory at Deportivo La Coruna. [Photo/Agencies]

If Portugal have proven that they can win without Ronaldo, Argentina continue to be heavily dependent on Messi. Just as the Albiceleste can thank their No. 10 for taking them to the final of the 2014 tournament in Brazil, Argentina owe their place in Russia to the 30-year-old.

Needing to win their final qualifier last October to book a World Cup spot, the two-time world champions beat Ecuador 3-1 in Quito, inspired by a superb Messi hat-trick. It is true that Argentina's attack continues to be the envy of rivals, with Manchester City's Sergio Aguero and Juventus pair Paulo Dybala and Gonzalo Higuain providing able support for Messi. However the midfield and defense lack world-class talent and continuity.

Coach Jorge Sampaoli has not stopped experimenting with players and formations since taking charge of the team last June, but he still seems unsure about his best starting lineup. Doubts were exacerbated by a 6-1 friendly loss to Spain in March. A lack of match fitness is also a concern for several key players. Among those sidelined in recent weeks have been Ramiro Funes Mori, Marcos Rojo, Lucas Biglia and Aguero.

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

"I won't bother Cristiano (Ronaldo) 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," said Santos. 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. Unsurprisingly, 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."