Lionel Messi and Cristiano Ronaldo: you can’t have a debate about their greatness without comparing them to each other. Much like the Joker and Batman, polar opposites who are defined in each other’s image, we’ve come to assess Messi and Ronaldo against each other, not in a vacuum but as a tandem. It’s the privilege and curse that comes with being the two best players on the planet right now.We were reminded of this dynamic at the start of Euro 2016, when Iceland defender Kari Arnason pointedly cited Messi in order to get further under Ronaldo’s skin, after the Portuguese’s uncharitable comments about the Icelandic team.A week of debate about Ronaldo followed - should we feel sorry for the aging superstar? Could he carry Portugal into the knockout rounds? - until his two goals against Hungary helped silence his critics, at least for a time. Days later Messi missed a penalty shootout in the Copa America final against Chile, a failure that fueled even more debate about his legacy that now includes three consecutive lost finals with Argentina. Then Messi announced that he’d no longer play for the national side.Naturally, this spawns further debate about how Ronaldo and Messi stack up. They’ve both put up ridiculous numbers at club level, but at the international level things are a bit more complicated.So, how do these two greats actually compare in the international arena?Basic recordsRonaldo: 60 goals in 130 caps since 2003Messi: 55 goals in 113 caps since 2005Tournament records Ronaldo in six tournaments: One final, two semifinals, one quarterfinal, one last-16, one group-stage exitMessi in seven tournaments: Four finals, three quarterfinalsBest tournamentRonaldo: Still the one that made him, at home in Euro 2004. Giving away a penalty in the opening game against Greece did not affect the young 19-year-old; in fact, it only spurred him on. He was brilliant from there on, especially in a blistering duel with Ashley Cole in the quarterfinal against England and then scoring the key first goal in the semifinal against the Netherlands.Messi: The 2014 World Cup. Messi winning the award for best player of the tournament may have caused controversy given his mediocre final, but it shouldn’t cover up the fact that he had dragged Argentina there without ever being at full pelt himself. Messi offered two match-winners, against Bosnia and Herzegovina and Iran, a last-minute match-winning assist in the second round against Switzerland, and then one of the moments of the tournament in the quarterfinal against Belgium when he played a glorious long-range pass. He was within inches of wholly dominating a tournament.Worst tournamentRonaldo: 2010 World Cup. Ronaldo was at his peak but ineffective in getting knocked out at the last-16 stage against Spain. His inconsequential goal in the 7-0 win over North Korea was his only international strike for 16 months.Messi: 2011 Copa America, as illustrated by the fact he got booed by his home crowd. This was at the height of the debate over why Messi performed better for Barcelona than Argentina. He started the tournament poorly, struggling to link up well with crowd favourite Carlos Tevez. Although he improved, Messi went out at the quarterfinals without a goal.Best international momentRonaldo: Scoring all four goals in Portugal’s 2014 World Cup play-off with Sweden, out-performing Zlatan Ibrahimovic in the process, indicated just how dependent his side were on him. Here, he rose to the moment emphatically.Messi: No real crowning moment, but a lot that brought him so close. Perhaps the most exhilarating was the run in the 2015 Copa America semifinal against Paraguay, when he so easily humiliated four players, pick-pocketing one, hopping a challenge, nutmegging another and then causing two to collide into each other.Worst international momentRonaldo: Arrogantly saving himself for the last penalty against Spain in the Euro 2012 semifinal shoot-out after doing so little in the match, and then not getting to hit it at all as the Spanish won.Messi: Curving the ball just wide of Manuel Neuer’s far post in the 2014 World Cup final. That was the big chance to end the all the debate about who’s the best. It made it all the more poignant that, less than a year later, Messi twice humiliated Neuer while playing for his much better club side, Barcelona, in the Champions League semifinal.Best international team they have played forRonaldo: Euro 2004. It wasn’t just the fact that this was the only one of his teams to get to the final. They still had enough of the brilliant Euro 2000 team to bring a 19-year-old through, and enough flair to get the best out of him. Ever since then, his Portuguese sides have become ever more cautious and more reliant on Ronaldo in a way that hasn’t been good for him.Messi: Copa America 2007. The most free-wheeling Argentine team Messi has played in. Argentina were somewhat unlucky that manager Alfio Basile was out-thought in the final by Brazil boss Dunga, losing 3-0. Ever since then, it’s never fallen quite right for Messi. Either the manager’s not been right, as in 2010 or 2015, or too many teammates have been off form, as in 2014.Overall ratingRonaldo: 7/10 - So many fine moments, but also too many early exits in which he was ineffective, even if it wasn’t all his fault. He at least can still rectify that at Euro 2016.Messi: 7.5/10 - Getting to more finals, and doing so much more than scoring, just lifts him past Ronaldo. There’s still such a huge sense of what might have been though.