Magalhaes, meanwhile, completed a £23million move to the Emirates from Lille.
Both Willian and Magalhaes have enjoyed promising starts to their Arsenal careers, helping the Gunners win their first three games of the 2020-21 season.
Xhaka, who joined Arsenal four years ago from Borussia Monchengladbach, has praised the club’s summer transfer activity and says Willian and Magalhaes have both brought ‘quality’ to the team.
‘With Willian and Gabriel, Arsenal brought a lot of quality and mentality into the dressing room,’ Xhaka told the Swiss Telegraphic Agency.
‘Willian knows how to win titles. And the extension with [Pierre-Emerick] Aubameyang was an important signal for all of us – we want to go back to the Champions League.’
Xhaka’s Arsenal career appeared to be over last season when he clashed with the club’s supporters during a Premier League match against Crystal Palace.
Former manager Unai Emery stripped the Switzerland international of the captaincy following the outburst.
However, Xhaka has impressed for the Gunners under Arteta and said: ‘One thing is certain, I wouldn’t be in London without him.
‘He was the decisive factor, with his philosophy, with his style, with his idea. I am really grateful to him for that.
‘We players saved a strange season with the last possible qualification for international business.
‘I don’t want to imagine how the reactions would have been if we had missed the Europa League.’