The 21-year-old Brazilian arrived at the Nou Camp from Santos last month for £48.6million with the brief of helping prolific Argentinian Messi in the Barca frontline.
Neymar received a rapturous reception from the Catalonian public but several figures associated with the club - including former manager and player Johan Cruyff - have expressed concern the young striker could hold Messi back while finding his feet in the Primera Division.
However, Messi has cooled concerns over his team-mate's progress, telling Marca.com: "He is a great player and he will have no problems adapting.
"He won't have any problems off the pitch either. He's a great lad.
"(His signing) adds a lot to the team. He is very strong in one-on-one situations and is going to make a difference."
Messi, who has scored 313 goals in all competitions for Barca, also said he was unconcerned over accusations of tax avoidance brought against him last month.
The 25-year-old and his father Jorge Horacio will appear for questioning in September as part of an investigation into alleged tax fraud in relation to the player's image rights.
"I am very calm," Messi said. "We have consultants who are handling these matters and we trust them. We hope to find a solution.
"I don't understand any of it and that's why we have lawyers."