The Brazilian international was officially confirmed as a Barca player back in May, and the four-time Ballon d'Or winner has called on Neymar to reproduce the form that has made him one of the most recognisable names in football.
"Hopefully he can continue to demonstrate the sort of performances that he's showed for Brazil and Santos," Messi told reporters.
"Hopefully Neymar can make a big contribution to Barcelona. I'm sure he will be a good signing for what we want to achieve."
Neymar finished with four goals as Brazil won the Confederations Cup last week.