Lionel Messi has won six Spanish league titles, three Champions League crowns and a record four world player-of-the-year awards. But he hasn't won a World Cup.
Cristiano Ronaldo won nine trophies with England's Manchester United, four more with Real Madrid in Spain and is a two-time world player of the year. But he too has never won a World Cup.
Together they have scored nearly 800 goals for club and country over the last decade. Yet if they both come home from this summer's World Cup empty-handed again, the number that might ultimately come to define their careers is zero.
Just ask Messi.
"I don't think any player can be considered a true great until they have won the World Cup," Messi told Goal.com last week. "I hope that I can do that and I hope I can do that this summer. But until then I don't talk about me as the best."
Everybody else does, though.
"He's the best. There is no other like him," said Pep Guardiola, Messi's former club coach at Barcelona. "We'll never see a player like him again."
Arsenal Coach Arsene Wenger agreed, comparing Messi to a character in a video game.
"He made the impossible possible," he said. "He is unstoppable. He is the best player in the world by some distance."
If Messi truly is a superman, though, then the World Cup is his kryptonite. In eight matches over two World Cups he has scored only once, with Argentina losing in the quarterfinals both times.
That's far from great. And Messi knows it.
"Messi might be regarded as the greatest player in the whole history of the game, but he would give all the medals he has won with Barcelona just to win one World Cup, that is how important it is for him," former Argentine midfielder — and World Cup champion — Ossie Ardiles said last week at a soccer forum in Jordan.
"To be considered alongside the top, top guys like Pele and Diego Maradona and so on, he not only needs to be in the World Cup but to win it."
This could be the summer that happens. Although host Brazil and European giants Spain and Germany are considered the tournament favorites, Argentina is ranked seventh in the world and, significantly, it has won the World Cup the last two times it was held in Latin America.
Plus Argentina is greatly improved from four years ago and will surround Messi with experienced, world-class players including Sergio Aguero and his Manchester City teammates Pablo Zabaleta and Martin Demichelis; Gonzalo Higuain of Italian club Napoli; Ronaldo's Real Madrid teammate Angel Di Maria; and Barcelona's Javier Mascherano.
Also working in Messi's favor is the fact Argentina is the giant of what appears to be a relatively easy group that includes Bosnia-Herzegovina, Iran and Nigeria, none in the top 24 in the latest FIFA world rankings.
Then there's his youth: Messi turns 27 next month, so even if he falls short this year he figures to have another shot at a World Cup title four years from now in Russia.
But he promises he isn't playing for his legacy in Brazil. He's playing for Argentina.
"I do not want to be world champion … so that people can say that I will be a great like Pele or Maradona," he told ESPN. "I want to do it to achieve this objective with the national team."
Portugal's Ronaldo — who, at 29, might be facing his last chance at a world championship — has said pretty much the same thing.
"My dream — and that of everyone — is to win something as important as the World Cup," he told a Spanish interviewer. "But we have to keep our feet on the ground. I hope Portugal can be among the best."
That Messi and Ronaldo have shared World Cup disappointment shouldn't be a surprise, because they've shared just about everything else — including a bitter rivalry — during their careers.
They've combined to win the last six FIFA World Player of the Year awards, five of the last six La Liga titles and they've finished 1-2 in goals in the Spanish league the last four seasons.
Oh, and they're also the two best-paid players in the world with Messi's new Barcelona contract, which will be announced this week, making he and Ronaldo the only two players in soccer history to earn more than $65 million a season in salary and endorsements.
However Ronaldo has had the better international career, with a Portuguese-record 49 goals in 110 games. (Messi numbers: 37 goals in 84 games, more than half those coming in friendlies.) And Ronaldo pretty much carried Portugal to Brazil, scoring all four of his team's goals in a two-leg victory over Sweden in Cup qualifying.
He'll also face the stiffer test in Brazil, with Portugal, ranked No. 3 in the world, matched with No. 2 Germany, the U.S. and Ghana in the tournament's so-called "Group of Death." Ronaldo, however, is the most feared player in that group.
"Listen, there's no question he's one of the best players in the world," Landon Donovan, the U.S.'s all-time leader scorer, said of Ronaldo. "He can single-handedly win games against some of the best teams in the world."
And if he doesn't do that in Brazil? And if Messi doesn't do that in Brazil? Doesn't matter, says Chelsea's Jose Mourinho, who coached Ronaldo and coached against Messi at Real Madrid, .
"Messi is great. I don't think he needs to win with Argentina to be great. Ronaldo is great. I don't think he needs to be world champion with Portugal to be great," Mourinho told Yahoo.
"But Maradona did it and [Zinedine] Zidane did it and Ronaldo Nazario and Rivaldo did it. Many of the big guys did it. So everybody's waiting for them to do it."