There's a GOAT on either side and when that happens, you know what comes next: Debate, endless debate. On social media, the war has already begun: Lionel Messi and MLS versus Cristiano Ronaldo and the Saudi Pro League. Which league is winning? Who would win head-to-head? Where will each league be in 10, 20, 50 years time?
It's natural, really. Debate is what makes sports so fun. 'Fan' is short for 'fanatic', after all, and fanatics are willing to support their side to the end.
That's one aspect of it: the fun side, or the toxic side depending on how deep you fall into the Messi vs Ronaldo Twittersphere. The reality, the on-field side, is in fact very different.
MLS and Saudi Arabia are two rising powers, both making moves that, at least in some way, has caused the powers in Europe to take notice. Both have picked up massive victories this summer and both are building major projects that have caught the public's attention. More than ever before, the world is looking at these two leagues outside of Europe's top-flights.
But, while fans love the idea of a rivalry between the two sides, the truth is that neither are really competing against one another. MLS and Saudi Arabia may have each signed their own version of the GOAT, but the way they do business outside of Messi and Ronaldo shows just how different the two leagues are approaching their own growth.