MIAMI -- Lionel Messi left the field in the 73rd minute of Inter Miami's 6-4 win over the Philadelphia Union at Nu Stadium on Sunday night, heading straight to the locker room after grabbing his left thigh.
The Inter Miami captain was grabbing at the upper part of his left thigh in the 70th minute after taking a free kick. He asked for a substitution and was replaced by Mateo Silvetti.
Messi required no additional help as he left the field or made his way to the locker room.
"As far as I know, we don't have a report on that yet, but he really was fatigued. It was fatigue," Miami coach Guillermo Hoyos said after the game. "Yes, it was fatigue. He was tired, the field was heavy, and rather than doubt, you always say not to take the risk."
Hoyos added that he hadn't spoken with Messi after the match.
The rare substitution for the Miami star so close to the start of the World Cup overshadowed a big comeback win and a record eight-goal first half.
The Union raced out to a 2-0 lead thanks to a pair of goals from Milan Iloski -- one from open play and one from the penalty spot -- before Germán Berterame pounced on Messi's cross to finish into an open net and cut the deficit.
The Union restored their two-goal lead minutes later when Bruno Damiani scored after Miami keeper Dayne St. Clair deflected a shot to him.
Miami came roaring back after conceding a third goal to the Union. Luis Suárez scored, then Berterame added his second goal and Suárez chipped in another to give the home side a 4-3 lead.
Shortly before the break, Sergio Reguilón was called for a handball after a VAR review, leading to Iloski's third goal to tie the score at 4-4.
The teams entered the break after the highest-scoring first half in MLS history.
The second half started in a torrential downpour, and the game slowed down accordingly, with neither side producing the same chances it did in the opening 45 minutes.
Minutes after Messi left the field, Suárez scored his third goal of the game from an unselfish assist by Berterame to give Miami a 5-4 lead in the 81st minute. Messi's Argentina teammate Rodrigo De Paul added Miami's sixth goal of the night. The final total is tied for the second-highest scoring regular-season match of all time.
MLS will now go on an extended break as players prepare for this summer's World Cup, with teams returning to the field in late July. With the win, Miami goes into the break in second place in MLS' Eastern Conference with 31 points, two behind leaders Nashville.
Argentina has not named its World Cup squad yet, but Messi was fully expected to participate for the defending champions. They begin Group J play against Algeria on June 16.
