LAS VEGAS -- When the U.S. men's national team and Mexico meet in Sunday's 2021 CONCACAF Gold Cup final, it will be the second time in 56 days that the longtime rivals have faced each other with a continental title on the line. And yet the two matches could not be more different in terms of the relative stakes involved.

Back on June 6, the sides met in the inaugural CONCACAF Nations League final, and it was the U.S. in desperate need of a win because, for the entirety of manager Gregg Berhalter's tenure, there had yet to be a victory that confirmed that the team was back on an upward trajectory.

A statement was needed, not only to generate some confidence in the coach's methods but also to give this generation of players something tangible to go with its undeniable talent. And, regardless of the wild sequence of events that took place during the game, the collective group stepped up, absorbed the pressure -- and a bottle or two to the head -- to ultimately walk away with a 3-2 win after extra time.

As for Mexico, while the loss stung -- they always do against the U.S. -- there was a belief that Gerardo "Tata" Martino's men had played well enough to win, having led twice and with the chance to make it 3-3 but for Ethan Horvath to save Andres Guardado's penalty. As it stood, El Tri would be back to fight another day.

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So what has changed heading into Sunday's encounter at Allegiant Stadium? In a word: expectations.

The U.S. came into this tournament with an intentionally youthful, inexperienced roster, with one fundamental reason the desire to give presumptive first-team regulars -- Christian Pulisic, Weston McKennie, Giovanni Reyna and others -- rest ahead of what is expected to be a busy season for both club and country.

But there was also a need to get a better idea of how impactful up-and-coming members of the player pool could be at the international level. This is especially important given that triple-fixture windows dot the horizon for World Cup qualifying, which begins in September, and depth will be tested.

Expectation-wise, this left the U.S. in a bit of a conundrum. Berhalter has said from the beginning that the goal was to win the tournament, regardless of roster construction. And yet there have been times when the team's youth has been trotted out as an explanation for shaky performances.

A 1-0 group-stage win against Canada, who had a slight edge in experience but also fielded some new faces in the absence of stars such as Alphonso Davies and Jonathan David, was seen as a case in point, yet it was not so much the young players who let the U.S. down that day but rather veterans who did not step up.

In Thursday's semifinal win, Qatar looked a cut above in the first half but were unable to find a way past the impressive Matt Turner in goal, which allowed the Americans to rally late in the game and seal victory through an all-important Gyasi Zardes goal.

That this U.S. squad has reached the final speaks well of its ability to adapt, grow and grind out results. Moreover, while injuries to the likes of defender Walker Zimmerman, midfielder Paul Arriola and defender Reggie Cannon have limited options, they have also given Berhalter data points on players like Shaq Moore, Miles Robinson, James Sands and Matthew Hoppe.

Given those developments, the U.S. would seem to be playing with house money on Sunday. Its objectives have largely been achieved and little is expected against the pre-tournament favorite. Yet Berhalter wants his side to be greedy and finish the job.

"We're not done, and that was the message to the team," the U.S. coach said after the semifinal. "It's nice to make the final, but we want to win the final. Our No. 1 goal is to win the Gold Cup. We said that before the Gold Cup, and we'll say it again."

By contrast, the stakes for Mexico could not be more different. This is a game it dare not lose, even if it almost cannot win; beating a short-handed U.S. team to claim a 12th Gold Cup title would prove little, even if there are a players absent like Raul Jimenez and Hirving Lozano.

But in the event of defeat, pressure would increase and doubts would be raised heading into World Cup qualifying. Would it even be enough to cost Martino his job?

There has certainly been that impulse at times in the past, but the tenure of predecessor Juan Carlos Osorio is instructive. The Mexico Football Federation stuck by him after a 7-0 thrashing by Chile in the 2016 Copa America Centenario quarterfinals, and that patience and emphasis on stability was rewarded with World Cup qualification and a famous victory over holders Germany in Russia.

This Mexico team has found a way to get results, even if the actual play has sometimes fallen short of its lofty standards. Jonathan dos Santos has been rallied around following the death of his father, and one would expect that its experience edge all over the field, but especially in a midfield led by Hector Herrera, will tell at some point.

Berhalter noted how poor his side was in terms of winning duels against Qatar, with just 42.7%, while the tackle success was even worse at 30%. If that happens again, the likes of Rogelio Funes Mori should benefit and make it a long night for a back line that has performed so well.

But the very nature of this long-standing rivalry means that another drama-filled chapter seems inevitable. Given the mental fortitude shown over the past few weeks by the U.S., as well as the must-win nature of the game for Mexico, expect another compelling encounter.