Playing at Nu Stadium, Messi opened the scoring with a rare headed finish before Casemiro sealed victory with a late header, giving new head coach Cristian “Kily” González a trophy in his first match in charge.
The victory provided an immediate boost for González, who had only recently taken over the team and had conducted his first training session just a day before the match.
"Leo [Messi] told me I was going to become a champion, and he made it happen," González said.
"Moving forward, this gives us a huge morale boost, it's a vital element for us, and while we've achieved this, we have to keep going."
Messi Heads Miami in Front
The breakthrough came in the 24th minute when Luis Suárez delivered a perfectly weighted cross from the right.
Messi timed his run, rose above his marker and headed the ball into the net to give Miami the lead.
The goal was significant not only because it put the MLS champions ahead but because it took Messi to 100 goals for Inter Miami in all competitions.
It was also an unusual way for the Argentine superstar to reach the landmark, with the vast majority of his goals having come from his left foot.
Casemiro then provided the decisive second goal late in the match, heading home to secure the trophy and complete a dream start for González.
Fastest 100 Goals of Messi's Career
Messi reached his Inter Miami century in just 115 appearances, making it the fastest he has scored 100 goals for any club or national team he has represented.
He previously required 188 matches to reach 100 goals for Barcelona and 174 appearances to reach the same milestone with Argentina.
Since arriving in South Florida in 2023, Messi has scored 76 goals in MLS, 14 in the Leagues Cup, eight in the Concacaf Champions Cup and one in the FIFA Club World Cup.
His latest goal also took his career tally for club and country to 929 goals.
Rodrigo de Paul, Messi's Miami teammate, said the achievement should not be taken for granted despite the frequency with which the Argentine continues to produce remarkable numbers.
"It's become a normality [for Messi] but it isn't," de Paul said.
"We have to enjoy him, admire him, see him with the love that he plays each game. Luckily, I've had him by my side for many years. I try to enjoy him to the maximum."
Another Trophy in Miami
Messi's arrival in Miami has already transformed the club's history.
He made an immediate impact after signing in 2023, leading Inter Miami to the Leagues Cup title only weeks after making his debut against Cruz Azul — the same club against which he scored his first goal for Miami.
The Argentine later helped the Herons claim the 2024 Supporters' Shield, with Miami setting an MLS record of 74 points during the regular season.
Messi also played a central role in the club's run to the 2025 MLS Cup title, further establishing the team's position among the leading sides in American soccer.
The Campeones Cup victory now adds another trophy to that rapidly expanding collection.
A Dream Start for González
González's arrival had been delayed by the need to secure his work permit. Inter Miami reached an agreement with the Argentine on August 27 to replace interim coach Guillermo Hoyos, but he was unable to formally take charge until the paperwork was completed.
After finally arriving in Miami from Argentina and leading his first training session on Tuesday, González had little time to prepare for his opening match.
The result could hardly have been more memorable.
With Messi scoring his 100th Miami goal and the team lifting another trophy, González began his tenure with silverware and a significant boost in confidence.
Messi also enters the remainder of the season in prolific form. The World Cup winner leads MLS with 19 goals in 22 games this season, adding another chapter to a career that continues to produce milestones even in its later stages.
For Inter Miami, the message from the Campeones Cup was clear: Messi remains central to the club's ambitions, while González now has an early trophy to build upon as he begins his tenure.