Willian says there is "no chance" he would have stayed at Chelsea if Antonio Conte had remained as the club's head coach.
Conte was replaced by fellow Italian Maurizio Sarri at Stamford Bridge, with the new man in charge seeing Chelsea win 3-0 at Huddersfield Town in their Premier League opener on Saturday.
With Eden Hazard not deemed fit enough to start, Willian was included in Sarri's team, joining Alvaro Morata and Pedro in a three-pronged forward line.
But the Brazil international has confirmed he would have sought a transfer from Chelsea had Conte not been dismissed by the Blues.
"Would I be here if Conte stayed? No chance. No," Willian told reporters.
"I'm here. I'm here because I want to play for Chelsea. I will only leave if Chelsea want me to go."
Willian was linked with a move to Manchester United during the transfer window, with the 30-year-old confirming he would be interested in working with former Chelsea boss Jose Mourinho again.
Barcelona also reportedly had a series of bids turned down for Willian, who made no secret of the breakdown in his relationship with Conte, even placing trophy emojis over the coach in a social media post, although he later blamed that on his daughter.
Goals from N'Golo Kante, Jorginho and Pedro helped Chelsea enjoy a winning start under Sarri, with Willian enjoying the style of play under the former Napoli coach.
"We have a lot of players with quality up front, players like Eden Hazard and Pedro. Players like that want to play football," Willian added.
"That's why Sarri talked about 'fun' football because he wants to build from the back. This is what we will try to do this season.
"This is what we do in Brazil and are trying to do here, playing with skill and movement and the manager told us to do that."