Willian insists there is "no chance" he would still be at Chelsea if Antonio Conte had remained in charge.
The Brazil international was linked with a move away from Stamford Bridge for much of the summer with the likes of Manchester United and Barcelona interested.
It has been widely reported that Willian was one of a number of key Chelsea players whose relationship with Conte deteriorated last season - with the 30-year-old winger quoted earlier this month claiming that the former Blues boss was "very difficult to work with".
Rumours of Conte's sacking hung over the club all summer and, despite returning to take the start of pre-season training, the man who delivered the Premier League title in 2017 was soon replaced by Maurizio Sarri.
Willian has since revealed he turned down Barcelona to remain at Chelsea and, having played 76 minutes of their opening-day victory at Huddersfield, said he is still at the club because Conte has gone.
When asked if he would be at Chelsea with Conte still at the helm, he said: "No chance. No. I'm here because I want to play for Chelsea. I will only leave if Chelsea want me to go."
After starting their Premier League life under Sarri with a comfortable 3-0 win at the John Smith's Stadium, Chelsea welcome Unai Emery's Arsenal to west London on Saturday.
Despite a good recent record against the Gunners, Chelsea struggled against their rivals during Conte's reign.
Willian believes the fresh tactical approach can help Sarri secure a win over fellow new Premier League boss Emery.
"I think we have a good chance to turn the results around against them because now we have a different way to play football," he said.
"The manager tells us to play, to enjoy ourselves on the pitch, with responsibility. Now we have a different style, that's why we can create problems for Arsenal (on Saturday)."
Meanwhile, West Ham midfielder Edimilson Fernandes has joined Serie A side Fiorentina on a season-long loan.
The 22-year-old has slipped down the pecking order at the London Stadium after new boss Manuel Pellegrini brought in 10 new players over the summer.