Cristiano Ronaldo and Lionel Messi have been at the heart of a heated and largely unresolved discussion over who is the best player in soccer history for more than a decade.

They might still be a part of that debate a decade from now. Only then will the inquiry become, “Who were those two guys who came before Kylian Mbappe and Erling Haaland?”

That may appear to be a reach, but consider the data.

Ronaldo, 38, and Messi, 36, changed history, redefined brilliance, and propelled the sport to new heights. Soccer is more popular, profitable, and well-played than it has ever been, and Ronaldo and Messi, who defined an era if not an entire sport, are major reasons for this.

They pushed each other for much of their careers in Spain’s La Liga, combining for 19 league championships, four Champions League titles, and 13 Ballon d’Or awards, achieving levels of greatness together that neither could have reached alone.

Mbappe and Haaland, on the other hand, have been even better at comparable stages in their careers. And it’s not unreasonable to believe they could stay there.

Begin with the numbers. Ronaldo of Portugal is the most prolific goal scorer in history, with 870 goals for five clubs (Sporting CP, Manchester United, Juventus, and Al Nassr, in addition to Real Madrid). According to the Zurich-based International Federation of Football History and Statistics, Messi, an Argentine who played for PSG and Inter Miami after leaving Barcelona, has 821 goals, while the once-incomparable Pele is a distant third with 762.

Ronaldo and Messi are both among the top ten all-time assist leaders, having contributed to over 1,110 goals in their careers.

Mbappe and Haaland are on track to outperform each other. Mbappe is less than a week over his 25th birthday and already has 306 goals and 127 assists, which is more than Messi or Ronaldo had at the same age. Haaland, who will turn 24 next summer, has 232 goals for club and country and is older than Messi and Ronaldo.

Messi and Ronaldo, on the other hand, were just getting started. Messi set a club record with 73 goals in 60 games for Barcelona in his age-24 season, 2011-12, kicking off a six-year streak in which he averaged more than 54 club goals a season. During that period, Ronaldo was only one goal a season behind, but he went on to score more than 400 times after turning 30.

Can Mbappe and Haaland compete? So why not? They’re just getting started.

However, numbers do not tell the entire picture; it is what those numbers add up to that determines greatness.

Mbappe led Monaco to the Ligue 1 title and the Champions League semifinals as a 17-year-old. In six seasons at Paris Saint-Germain, he won five additional French crowns, two alongside Messi, and reached the Champions League semi-finals twice. He has already appeared in two World Cup finals, winning one of them. He also topped the competition in scoring in 2022 with eight goals and tied for second with four in 2018.

Only five players in history have scored more World Cup goals than Mbappe, and only one has appeared in more finals. Did we mention he’s only 25 years old?

Before his 25th birthday, Messi had won five La Liga titles and three Champions League crowns, yet it took him 17 years to reach his second World Cup final and earn his sole title. Mbappe may have more to come: He might end up being the most dominant player in World Cup history, playing for a French team ranked second in the world in an era when the competition is expanding.

“Messi has done so much in his career and over so many years, and he is fantastic.” “He has been the best for several years,” Fabio Capello, who won seven league championships and a Champions League triumph as a coach, remarked last spring at the end of the final European season in which Messi or Ronaldo was featured. “But Mbappe is better right now.” He’s swift, he’s strong, and he scores goals.”

Mbappe, like Messi, is a fantastic passer who can score himself — he’s on track for his sixth consecutive 30-goal season and sixth straight league scoring title — or set up teammates — he topped the league in goals and assists two years ago, with 17 assists, the most in a French season in six years.

Mbappe, the youngest player ever nominated for a Ballon d’Or, has never won the top individual honor in soccer, finishing as high as third in voting only once. This year, Messi won the award for the eighth time in a row.

Haaland, who finished second in the Ballon d’Or voting, has seen his greatness limited to his club career thus far. Haaland led Manchester City to a European triple last season, his first in the Premier League after two seasons in Norway and three years split between the Austrian and German Bundesligas. This season, he has 19 goals in 22 appearances in all competitions, trailing Mbappe, who has two more in the same number of games. Haaland has 178 club goals in 179 games over the last four full seasons.

However, his national team, Norway, has not competed in a World Cup this century and has only appeared in the European Championship a month before Haaland was born. As a result, he has only made 29 appearances for his country, scoring 27 goals. According to the German website Transfermarkt, Mbappe has played more than twice as much for France, scoring 46 times.

Pep Guardiola, who coached Messi in Barcelona and now manages Haaland in England, describes Messi as the “most complete player I’ve ever seen, in vision, passes, dribbling, and competitiveness.” That makes [comparing] with anyone difficult.”

“Hopefully Erling can be close like Leo,” he went on to say. “It will be fantastic for us and the team’s future.” But comparing myself to the Argentine player serves no purpose.”

Can Mbappe and Haaland keep up this pace? In a nutshell, yes.

It will be critical to avoid injuries. Only once in the last 17 years has Messi played fewer than 36 games. Ronaldo was a teenager in Portugal the last time he played fewer than 31 games in a season. The ongoing extension of club and national team calendars will be both an opportunity and a risk for Mbappe and Haaland; an opportunity because more games means more chances to score and win trophies, but a risk since it increases the threat of injury. Haaland, a 6-foot-4, 194-pound physical beast, appears especially well-suited to manage the increased effort.

Messi and Ronaldo have set a high standard, but Mbappe and Haaland may one day surpass it.