For MLS, Concacaf's Champions Cup remains the ultimate litmus test

Look at a number of different metrics, and there appears to be mounting evidence to support the idea that Major League Soccer has pulled even or even surpassed Mexico's Liga MX when it comes to its level of play.

In 2022, the Seattle Sounders became the first MLS team in more than two decades to win the Concacaf title. The American/Canadian top flight lured the sport's biggest superstar midway through last season, and Lionel Messi immediately helped Inter Miami win the new Leagues Cup tournament in which all 47 MLS and Liga MX teams participated.

Eight MLS clubs are currently in the last 16 of this year's Concacaf Champions Cup compared to just five from Liga MX. The upward trend is obvious. Right? In truth, it's a little more complicated than that. 

As much progress as MLS has made toward closing the gap with Mexico's best over the last decade, it still has plenty to prove. And there's no better competition to do that in than the Champions Cup. 

The rebranded Champions Cup (it was known as the Champions League from 2008-2023) resumes this week with several intriguing MLS-Liga MX matches. Tuesday's doubleheader begins with the Philadelphia Union hosting Pachuca and concludes with Tigres' visit to Orlando City (coverage begins at 7 p.m. ET on FS2 and the FOX Sports app). 

On Thursday, Monterrey striker Brandon Vazquez faces his former club when the Rayodos open their two-leg, total-goals series at FC Cincinnati. The decisive second legs will be played south of the border next week.

As incentivized as MLS and Liga MX are to promote the Leagues Cup, a joint venture between the two entities that is staged exclusively in the U.S. and Canada, the Champions Cup remains the better measure of where each domestic circuit actually stands.It's the only time MLS teams must travel to Mexico and perform in truly hostile environments. And that makes a huge difference.

American teams won the Concacaf title twice in the MLS's first five seasons, when the entire Champions Cup was held in the U.S. But after the current home-and-home format was adopted, no MLS side even reached the final for another decade. A Liga MX team claimed every edition of the continental championship from 2006-2021 before the Sounders mercifully ended MLS's 20-year run of futility.

But it was the same old story last spring, as León topped MLS Cup-holder LAFC in the final. LAFC coach Steve Cherundolo didn't mince words afterward, laying at least some of the blame on MLS's extensive salary restrictions, which allow for just three "designated" players who earn far more than most of their teammates. Meantime, Liga MX lets its teams spend however they see fit. The result has been an almost insurmountable depth advantage for Mexican clubs.

"As an MLS team in tournaments like this, if you want to consistently compete in finals and win these, you're going to have to rethink your roster rules and regulations," Cherundolo said. "There's a little more money on their side of the table, and money in this game buys quality players."

With Messi on board and the 2026 World Cup coming to North America in two years, there are rumblings that MLS owners will loosen the purse strings significantly at long last, perhaps as soon as next season.

FIFA's expanded Club World Cup will also be hosted by the U.S. in 2025, and MLS and Liga MX will have at least two participants each. León, Monterrey and Seattle are already qualified, while the host nation will receive one additional berth. The final spot goes to whoever wins the Concacaf Champions Cup in June.

Even without additional resources, MLS is getting closer. The American teams still in contention for this year's crown have a real shot, and they're all hoping to prove that Seattle's win wasn't an aberration, but another sign that the tide is beginning to turn.

The toughest test yet for Lionel Messi and Inter Miami

Miami's Leagues Cup win earned the Herons a spot in this season's Champions Cup, which raises the tourney's profile considerably. The competition will tell us plenty about Miami, too. While Miami is off to an unbeaten start to the MLS regular season, they'll now have to fight on multiple fronts. Their core four of former Barcelona stars Messi, Jordi Alba, Sergio Busquets and Luis Suárez are all well into their 30s. Fatigue could be an issue. The games will come thick and fast.

Miami also faces a formidable opponent in the round of 16: Nashville. The rematch of the Leagues Cup final kicks off with Thursday's opener in Tennessee (9 p.m. ET, FS2 and the FOX Sports app).

Mexico gets a Champions Cup Súper Clásico

The most-watched round of 16 series on both sides of the Rio Grande will involve Liga MX's most popular clubs: Club América and Chivas Guadalajara. The latter will host Wednesday's opener (10 p.m. ET, FS2 and the FOX Sports app), with the return leg on March 13 at Mexico City's iconic Estadio Azteca.

Both sides are stocked with past, present and future Mexican national teamers, including recent El Tri greats Jonathan dos Santos of América and Chivas' Javier "Chicharito" Hernandez. Each team also boasts a member of the USMNT in Cade Cowell (Chivas) and Alex Zendejas (América.)

Cincinnati-Monterrey about more than Vázquez's homecoming 

If this winter's transfers of Cowell and Brandon Vázquez from the San Jose Earthquakes and FCC respectively further underscores Liga MX's current financial superiority, the two Americans' performance in Liga MX so far suggests that MLS is more challenging.  

Cowell has as many goals through seven games in Liga MX as he did in 23 MLS appearances last season. Vázquez has four in six matches with the Rayodos after scoring eight times in 29 games for Cincy last year.

What that may or may not say about the level of the two leagues doesn't really matter, not with Monterrey and FCC about to go toe-to-toe for a spot in the quarterfinals. That series, which kicks off in Ohio on Thursday (7 p.m. ET on FS2 and the FOX Sports app), will reveal a lot more. 

Doug McIntyre is a soccer writer for FOX Sports. Before joining FOX Sports in 2021, he was a staff writer with ESPN and Yahoo Sports and he has covered United States men's and women's national teams at multiple FIFA World Cups. Follow him on Twitter @ByDougMcIntyre.