Messi, who turned 37 this week and has been suffering muscle niggles, required brief medical treatment on his thigh during Argentina's 1-0 victory over Chile at the US-hosted tournament.
But he completed the 90 minutes, shaving the post with one long-range shot and was at the heart of Argentina's attacks.
"It bothers me a bit, but I was able to stay on until the end. I hope it's nothing serious... I wasn't able to move properly because of the bother," he said, acknowledging it might be wiser to sit out the Peru game on Saturday.
"Let's see how the next few days go, how I recover. We've taken an important step to qualify and be relaxed. It's a lot of games, a lot of travelling," added Messi, saying he had also suffered from a sore throat and fever before the Chile game.
With a 2-0 win over Canada also under their belt, world champions and tournament favourites Argentina are looking comfortable in the early stages of the Copa América even if not at their scintillating best.
They top Group A with six points, ahead of Canada on three after their victory over Peru.
Argentina are happy to have started the Copa with routine wins after the unwanted drama of their last major tournament when they opened the World Cup in Qatar with a 2-1 defeat to Saudi Arabia in one of the all-time shocks.
Victory at the MetLife Stadium in New Jersey on Tuesday, thanks to a late Lautaro Martinez goal, helped Messi bury one of the worst moments of his career at the same stadium eight years ago.
His penalty shootout miss helped condemn Argentina to an agonising loss to Chile in the 2016 Copa América final, leaving an inconsolable Messi vowing to quit international football after yet another failure with his national side.
Coach Lionel Scaloni would not say whether he would rest Messi against Peru, to keep him fit for the quarter-finals, but Argentine football commentators assumed he would do just that.
Having won myriad accolades at club level with Barcelona from an early age, it has only been in the twilight of his career that Messi was finally able to triumph with Argentina at a major international tournament and match the godlike status of Diego Maradona in his football-crazy home country.
He captained Argentina to triumph at the last Copa América in 2021 and at the Qatar World Cup in 2022.
With fans wondering if this is his final international tournament, Scaloni has urged them to enjoy watching Messi rather than speculate about his future.
The stage does appear set for another potential Messi fairy-tale. Rivals Brazil are on a poor run of form and only managed an opening 0-0 draw with Costa Rica, and the July 14th Copa final takes place in Florida where Messi plays for Inter Miami.
