Luiz Felipe Scolari has backed Arthur to become Andres Iniesta's long-term replacement when he swaps Gremio for Barcelona.
Scolari gave Arthur his professional debut in 2015 and has watched from afar as the midfielder has gone from strength to strength.
Arthur established himself as a first-team regular last season and his performances brought interest from Europe's top clubs – including Chelsea and Atletico Madrid.
However, it was Barca who won the race for his signature and Arthur will move to Camp Nou in January 2019 after the Catalan giants agreed an option to sign him for €30 million.