The 22-year-old has joined from Porto in a £34million deal, bringing creativity to the midfield and also an option on the right wing where Arsenal have been so reliant on Bukayo Saka.
It follows the arrival of Brazilian teenager Marquinhos and the Gunners will hope there is more to come, with Gabriel Jesus, Raphinha and Lisandro Martinez all strongly linked with a move to the Emirates.
The club are particularly confident that they will win the race to sign Jesus, with his representatives travelling to England to wrap up a transfer to Arsenal.
Reacting after Vieira was unveiled by the club, Edu spoke about the work that went into the deal while revealing that there have been encouraging talks with other potential signings.
“This summer is just the consequence of what we’ve been working on a lot, to try to find the best players, the best targets,” Edu told the club’s official website.
“We identify really what we need in the squad, so when we started this summer, we are prepared.
“Fabio is a good example because we moved quickly because we prepared to get Fabio a long time ago and then when we face it, we make things happen.”
He added: “Yes I think we still have some good conversations and positive conversations to be fair. I hope we can give to the fans some good news.”