Barcelona marched to the La Liga title again last season but want to do better in the Champions League and Ernesto Valverde has strengthened his squad to help mount a challenge.
Clement Lenglet, Malcom, Arturo Vidal and Arthur have all arrived at the club and Messi is particularly impressed by the latter pairing, who he believes both offer plenty to the midfield.
"I didn't know much about Arthur before [he joined], but he's really similar to Xavi," he said. "He's really safe and reliable [in possession]. He has the style of a player who has come through La Masia.
"He plays well over short distances, he doesn't lose the ball. He's got to grips really quickly with the team's dynamic. Barca fans always want players with good feet.
"We defend with the ball. Players like Arturo Vidal are necessary. He's the type of player who does everything well, with the ball and also with the muscle that he has."