Between them Messi and Ronaldo have monopolised the past six world player of the year awards. But each have attended the last two World Cups and failed to even get near the trophy. Messi has scored just one goal at the finals, Ronaldo only two. (Agencies)
Now though the weight of Argentinian hopes rests on Messi's slight shoulders. Portugal are desperate for Ronaldo's goals to get out of one of the most difficult groups in the contest.
The Brazil World Cup could finally decide whether the name of Messi or Ronaldo is etched into football legend alongside the Peles and Diego Maradonas and Zinedine Zidanes. It is the competition which transforms reputations.
The softly-spoken Messi is 26, just 1.69 metres (5ft 7inch) tall and 67 kilogrammes (148 pounds) in weight. But his goalscorer record and brilliance pack the same weight as the 29-year-old Ronaldo -- 1.85m (6ft 1inch) and 80kgs (176 pounds) -- who revels in his glamour lifestyle.
Messi capture three Champions League wins with Barcelona while Ronaldo responded by adding a crown for Real Madrid last month to his earlier success with Manchester United.
Both average more than 50 goals a year in all competitions for their clubs.
Ronaldo is the world's most recognisable and marketable footballer, according to the Repucom, a sports marketing research company.
But Messi remains the world's most valuable footballer on the market, according to the Swiss-based CIES Football Observatory. It put the Argentine's value at 216 million euros ($294 million), while because of his age Ronaldo was worth just 114 million euros.
Reaching Pele Heights
The case for the elevation of Messi and Ronaldo to the almost deified heights of Pele and Maradona would surely be unanswerable were either to lift the trophy on July 13 in Rio.
"Both players are incredibly great athletes and both have outstanding qualities. Both can win a match in their club or national team on their own," said Ottmar Hitzfeld, the respected German coach who will be in charge of Switzerland at the World Cup.
But the World Cup, high pressure over one month, is vastly different from the Spanish league and Champions League duties which Messi and Ronaldo so brilliantly execute week in, week out.
Maradona is adamant that "Messi doesn't have to win the World Cup to be the best in the world."
For the 1986 world champion, "one world title more or one less can't take anything away from anything (Messi) has achieved to be where he is today."
Between them Messi and Ronaldo have monopolised the past six world player of the year awards. But each have attended the last two World Cups and failed to even get near the trophy. Messi has scored just one goal at the finals, Ronaldo only two.