The FIFA World Cup will undoubtedly place great focus on a number of tournament favorites but another storyline that could emerge is the rivalry of Cristiano Ronaldo and Lionel Messi.

This perennial debate over the best player in the world is usually a major conversation throughout the regular season due to the fact that the two titans of the sport play for rival clubs Real Madrid and Barcelona. The rivalry between Portugal and Argentina is non-existent but there is a chance that these two superstars could wind up meeting up in the tournament. Here is a look at how Ronaldo and Messi look heading into the tournament.

Cristiano Ronaldo won the Ballon d'Or in 2014 and thus dethroned Messi for the first time in four years. His victory came on the heels of a tremendous finish in 2013, including a four-goal performance against Sweden in the World Cup qualifiers late in the year. After his Ballon d'Or win, Ronaldo seemingly slowed down a bit and goal scoring became rarer for the superstar. However, he ultimately finished the season tied for Europe's leading scorer and set new records with a tremendous performance in the Champions League. Ronaldo scored 31 goals in 30 Spanish League matches; he scored 34 goals in 34 games a year earlier. During the Copa del Rey Ronaldo scored three goals in six games, but missed out on the final due to injury. It was this injury that ultimately clouded the final weeks of the season for Ronaldo as he struggled with his form while Real Madrid wobbled to the finish line and missed out on winning the treble. During the Champions League final, Ronaldo was virtually invisible; he had 16 goals in 10 games thus far in the tournament and would add his record 17th on a penalty kick to make the score 4-1. His 17 goals are now the highest marker ever for a scorer during a Champions League season. Messi's best total? Fourteen goals. But the injury that plagued the end of his season would continue to haunt Ronaldo and the superstar became a daunting question mark in the weeks leading up to the World Cup. Recent reports indicate that the Portuguese superstar will be ready for Portugal's opener against Germany, a huge boost for an often offensively-punchless Iberian team.

Ronaldo's international career has had its ups and downs. While he is the all-time leading scorer for Portugal, he only scored one goal in the 2010 World Cup and has a total of two World Cup tallies throughout his career. At age 29, this is likely to be the defining World Cup of his career.

While Ronaldo had a great year, Messi had a horrific one -- by his standards. Argentina's captain scored 28 goals in 31 Spanish league matches and finished the year with 41 goals in 46 matches. That is a rather wondrous figure by most standards but it pales in comparison with Messi's 60 goals in 50 games a year ago or his 92 goals throughout 2012 in all competitions. What emphasized Messi's numbers all the more was the fact that his club Barcelona did not win a single trophy during 2013-14. Messi struggled with injury throughout the year and it was that issue that ultimately proved his undoing. But now he heads into the World Cup with no health concerns and tremendous amounts of pressure. Messi is expected to lead Argentina back to glory for the first time since Diego Maradona did it in 1986. He has an all-star supporting cast, but he is the one who will get the spotlight. He has been great over the years for Los Che, but he needs to score a goal in this tournament; he did not score a single goal four years ago and only has one goal throughout his World Cup career. Messi has never won a major tournament with Argentina (something Ronaldo has not done either), but he must deliver for a Championship-hungry nation.

Who will have a better tournament? Ronaldo or Messi?