The Brazilian announced his departure from Chelsea yesterday, on his 32nd birthday, and he is now poised to pen a three-year contract with the Gunners.
Arsenal manager Arteta pushed for the deal as he has real confidence in the Premier League star, who was in top form for London rivals Chelsea post-lockdown.
While Willian will add a new dimension to the Gunners’ attacking armoury, they need to plug other holes in the team.
Arteta will have a strong array of forwards once Willian joins which includes Pierre-Emerick Aubameyang, Nicolas Pepe and Alexandre Lacazette.
Although Daily Star Sport understands the latter will go to Atletico Madrid for £30m once Aubameyang’s new contract is sorted in north London.
In midfield and at the back, meanwhile, Arsenal have long-standing issues that need addressing if they are to challenge for Champions League qualification next season.
Arsenal only qualified for the Europa League this term by beating Chelsea in the FA Cup final at Wembley behind closed doors at the start of August, having finished eighth in the Premier League table.
Following Unai Emery’s sacking in December, Arteta could only guide his current crop of players so far in recovering their season, as they ended up in their lowest position in the top flight since 1995, pre-Arsene Wenger.
The most likely deal to happen after Willian joins is regarding Dani Ceballos’ future.
The creative Spain midfielder earned Arteta’s trust in the second half of the campaign and became a regular figure in the starting XI.
Arsenal want to keep the Real Madrid loanee in the capital for at least next season, and talks are ongoing over a second short-term deal.
Ceballos, 24, is keen to remain at Arsenal under Arteta, having formed a strong partnership alongside Granit Xhaka, who at one stage looked destined to leave under a cloud after he fell out with supporters.
However, Arsenal face the prospect of replacing two other midfielders in the form of Matteo Guendouzi and Lucas Torreira.
Arteta has not been impressed with French ace Guendouzi’s attitude, while AC Milan are keen to sign Torreira, who has struggled for regular game time.
While Ceballos staying would be a boost, Arteta would also require another proper holding midfielder, and Arsenal are continuing to purse Atletico Madrid’s Thomas Partey.
Arsenal have been told they need to pay up his £45m buyout clause if the 27-year-old is to be prised away from the La Liga giants.
And the Gunners are working to find the funds to get him, as Arteta wants a dynamic central midfielder to stiffen the spine of his side, Football London say.
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Defensively, the Spanish boss has a couple of potential options to add to his planned two midfield signings.
Ligue 1 duo Malang Sarr and Gabriel Magalhaes are both admired at Arsenal, and each have bright futures ahead of them.
France Under-21 international Sarr is now a free agent after his contract ran out at boyhood club Nice, and he is weighing up his options.
Gabriel, meanwhile, is known to have a number of suitors, including some of Arsenal’s Premier League rivals in the form of Everton and Manchester United.
Napoli also like the 22-year-old, who is valued at around £27m, but he would be a top quality addition to the squad alongside William Saliba, who finally links up with his Arsenal team-mates this summer a year after signing.
Given Saliba is coming in, Arsenal only need one other centre-half from their wishlist, and it will pose questions regarding the futures of Sokratis Papastathopoulos, Rob Holding and Shkodran Mustafi.
Arteta will ultimately be conducting a lot of reshaping in those areas, as he only has a limited transfer budget to work with.