Messi magic continues as Argentine leads Inter Miami to Leagues Cup title
Messi opened the scoring in the 23rd minute, notching his 10th goal of the inaugural tournament with a blistering shot from distance that flew past multiple defenders and into the top left corner of the net.
Nashville's Fafa Picault levelled for the home team in the 57th minute and both teams then came agonizingly close to taking the lead in a rollercoaster second half.
In the shootout, Nashville goalkeeper Elliot Panicco missed the final kick of the night to deliver Inter Miami, who joined the league in 2020, their first trophy.
Messi's overjoyed teammates tossed the Argentine in the air as ecstatic Miami co-owner David Beckham shook his fists above his head in triumph.
"It's a huge honour to play a role in our first win in a final," said Miami goalkeeper and man of the match Drake Callender, who saved two goals in the shootout and converted his own penalty.
"It's pretty surreal and very emotional. This team works so hard day in and day out, and to have it come down to the very end... it's amazing to see the grit and the belief. It's something special and I'm blessed to be part of it."
Miami have the worst record in MLS this season, but Messi's arrival has ignited an offensive explosion with the squad scoring 22 goals in their last seven games.
The trophy is Messi's 44th, the most by any player. The seven-time Ballon d'Or winner was named player of the tournament, which includes teams from MLS and Liga MX.
"It was a tight game for both teams, either could have won it," Miami head coach Gerardo "Tata" Martino said.
"It ended in a tie and I thought a tie was fair. And obviously, it ended in penalties, which takes a lot of calmness, great capacity from the goalkeeper, and we won the game."
The Miami club, who appointed Martino as coach last month and signed Messi's former Barcelona team-mates Jordi Alba and Sergio Busquets, have also secured a CONCACAF Champions League berth with their Leagues Cup run.
"We weren't doing well before and we had to incorporate a lot of new players," said Martino.
"I'm very impressed with the way we came together."