Signed on a free transfer from London rivals Chelsea in the summer, Willian hit the ground running in Arsenal red when he provided two assists on his debut in a routine win at Fulham.
But he has yet to get on the scoresheet for the Gunners and has failed to provide a Premier League assist since his fine display at Craven Cottage.
A niggling ankle injury saw him sidelined for a short spell but he has struggled to make the impact many would have anticipated from a man with seven years of experience in English football behind him.
Willian, 32, has yet to click completely with his new team-mates but Arteta is backing that to change - with Aston Villa heading to the Emirates Stadium on Sunday afternoon.
"I think he started really well with his first game against Fulham," Arteta said of the forward.
"Then we've been changing the front three, he had an injury and he didn't have any time to train, he didn't have any pre-season, he was later than the others.
"They need to generate that cohesion, that understanding and those relationships on the pitch between the front players, the wide players in order for things to work better.
"I can see a development in the last two games and the understanding of things that we do but he's not used to.
"He's getting better and better and we all know the quality that he has and he's a great option to have on the pitch."
Willian averaged seven goals a season during his six-year stint at Chelsea and Arteta will be hoping to see some of that form in north London before too long and has backed the former Anzhi Makhachkala man to prove his worth.
"He's a player who can make a difference," added the Spaniard.
"He's got the ability to find that last action to open the door when everything is really tight.
"To score a goal, create an assist and the personality and understanding that he has on the pitch to manage the game we need in certain moments."
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