Barcelona's Lionel Messi, left, reacts next to Juventus' Cristiano Ronaldo during the Champions League group G soccer match between FC Barcelona and Juventus at the Camp Nou stadiu...
AP Photo/Joan Monfort
Juventus' Cristiano Ronaldo holds a ball before scoring a penalty kick during the Champions League group G soccer match between FC Barcelona and Juventus at the Camp Nou stadium in...
AP Photo/Joan Monfort
Barcelona's Lionel Messi, left, shakes has with Juventus' Cristiano Ronaldo prior of the start of the Champions League group G soccer match between FC Barcelona and Juventus at the...
AP Photo/Joan Monfort
Juventus' Cristiano Ronaldo, center, gestures during the Champions League group G soccer match between FC Barcelona and Juventus at the Camp Nou stadium in Barcelona, Spain.
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Cristiano Ronaldo of Juventus, left, escapes a Dynamo Kyiv challenge during a Champions League, group G soccer match between Juventus and Dinamo Kyiv at the Allianz Stadium in Turi...
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Cristiano Ronaldo of Juventus, left, celebrates a goal against Dynamo Kyiv during a Champions League, group G soccer match between Juventus and Dinamo Kyiv at the Allianz Stadium i...
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Juventus players Cristiano Ronaldo, left, and Federico Chiesa in action against Dynamo Kyiv during a Champions League, group G soccer match between Juventus and Dinamo Kyiv at the ...
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Juventus' Alvaro Morata, center, celebrates with teammates Federico Chiesa and Cristiano Ronaldo after a goal during a Champions League, group G soccer match between Juventus and D...
AP/PTI Photo
Juventus' Cristiano Ronaldo celebrates after scoring during the Champions league, group G soccer match between Juventus and Ferencvaros, at the Allianz Stadium in Turin, Italy.
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Juventus' Cristiano Ronaldo celebrates after scoring a goal during the Serie A soccer match between Juventus and Cagliari, at the Allianz Stadium in Turin, Italy.
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Juventus' Cristiano Ronaldo sits on the field after a challenge during the Serie A soccer match between Lazio and Juventus at the Olympic stadium in Rome.
AP Photo/Andrew Medichini
Juventus' Cristiano Ronaldo scores on a penalty his side's fourth goal, during the Serie A soccer match between Spezia and Juventus, at the Dino Manuzzi Stadium in Cesena, Italy.
Massimo Paolone/LaPresse via AP
Juventus' Cristiano Ronaldo celebrates after scoring his side's fourth goal, during the Serie A soccer match between Spezia and Juventus, at the Dino Manuzzi Stadium in Cesena, Ita...
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Sweden's Gustav Svensson (13) tries to stop Portugal's Christiano Ronaldo during their UEFA Nations League Group stage soccer match at Friends Arena in Stockholm, Sweden.
Claudio Bresciani / TT via AP
Portugal's Christiano Ronaldo shoots a free-kick to score against Sweden during their UEFA Nations League Group stage soccer match at Friends Arena in Stockholm, Sweden.
Claudio Bresciani / TT via AP
Portugals Cristiano Ronaldo celebrates after scoring against Sweden during the game against Portugal during their UEFA Nations League Group stage soccer match at Friends Arena in S...
Janerik Henriksson / TT via AP
Portugal's Ronaldo celebrates after scoring against Sweden, his 100th goal, during the UEFA Nations League Group stage soccer match at Friends Arena in Stockholm, Sweden.
Janerik Henriksson / TT via AP
Juventus' Cristiano Ronaldo celebrates after scoring his sides' opening goal on a penalty during the Champions League round of 16 second leg, soccer match between Juventus and Lyon...
Marco Alpozzi/LaPresse via AP
Juventus' Cristiano Ronaldo, left, controls the ball as Lyon's Joachim Andersen defends during the Champions League round of 16 second leg, soccer match between Juventus and Lyon a...
AP Photo/Antonio Calanni
Juventus' Cristiano Ronaldo reacts during the Champions League round of 16 second leg, soccer match between Juventus and Lyon at the Allianz stadium in Turin, Italy.
Messi and Ronaldo have dominated football for more than a decade, with the pair winning 11 Ballon d'Or awards between them as debate rages over who is the game's greatest player