MIAMI GARDENS, Fla -- Argentina national team assistant coach Walter Samuel confirmed Lionel Messi's status continues to improve ahead of a Copa América quarterfinal against an undetermined Group B rival on July 4 at NRG Stadium.

Messi failed to feature for La Albiceleste on Saturday against Peru in the team's group-stage finale, after suffering an injury to his right hamstring during the game against Chile on Tuesday.

The team's coaching staff confirmed the captain remains on a day-to-day basis, but remained cautiously optimistic of a potential return after speaking inside the locker room at Hard Rock Stadium.

"He was in the locker room, we noticed him better," said Samuel, who took over coaching duties for Lionel Scaloni after he was given a one-match suspension by Conmebol.

"The situation is improving but it's a few days and the situation is premature to talk about. We'll talk about it on a day-to-day basis with him, and talk to the doctors."

Lautaro Martínez scored both goals as Argentina beat Peru 2-0 to top Group A with maximum points from three games.

"Leo is fine, we hope he can be in the next game. I dedicated the goal to him because I know what Leo means to us," said Martínez.

Ángel Di María also spoke optimistically of Messi's status.

"Leo is fine, he's recovering, we hope he will be ready for the next game. Today's victory is for him," he said.

Argentina now prepare to face the runners-up from Group B, likely Ecuador or Mexico, in the quarterfinals.

"They are different rivals," Samuel said. "We faced Ecuador in the last friendly. We know them, and have a capable coach. The physical part is a big deal, but they have a great technical quality too. They are playing this tournament well, and it'll be difficult."

"With Mexico, well we faced them in the World Cup. They have different characteristics but it'll be difficult. For now, we are happy and want to value this victory before focusing on the next match."

Argentina and Messi have four days before the game in Houston, and will look to travel to Texas on Monday morning.