Lionel Messi plays the ball in the semi-finals of the 2023 US Open Cup at TQL Stadium in Cincinnati, Ohio. AFP

Lionel Messi inspired Inter Miami to come back from 2-0 down to beat Cincinnati on penalties after their thrilling US Open Cup semi-final ended 3-3 after extra-time in Ohio.

Miami, who won the Leagues Cup on penalties against Nashville on Saturday, are now one win away from their second trophy since Messi joined the club last month.

The US Open Cup is American soccer's oldest and most important knockout competition, dating back more than a century to 1914 and is similar to England's FA Cup or Spain's Copa del Rey.

Miami will host the Houston Dynamo in the final on September 27 after the Texan side beat Real Salt Lake 3-1 after extra-time.

A month ago Cincinnati, who are top of Major League Soccer's standings while Miami are bottom, would have been clear favourites. But the Florida team are now a very different side to the one which was winless in their 11 league games before the arrival of the Argentine.

In the intense heat, with temperatures over 100 degrees fahrenheit (38 Celsius) at kick-off, Miami's unbeaten run since the signing of Messi and Spanish pair Sergio Busquets and Jordi Alba looked to be coming to an end.

Lionel Messi plays the ball in the first half against the FC Cincinnati at TQL Stadium. Reuters

Inter trailed 2-0 with 22 minutes remaining before the Argentine delivered two perfect assists to striker Leonardo Campana to take the game into extra-time.

Messi's compatriot Luciano Acosta had put Cincinnati ahead in the 18th minute and American striker Brandon Vazquez doubled the home side's lead with a fine strike from the edge of the box in the 53rd minute.

In the 68th minute, Messi whipped in a free-kick from the left which was headed home by Campana to breathe some life into what had been a tired display from Gerardo Martino's side.

Cincinnati thought that they had made it 3-1 but Yuga Kubo's effort was ruled out for handball.

Agence France-Presse