Willian says he wanted to stay at Chelsea before joining Arsenal last summer.
The Brazil international spent seven seasons at Stamford Bridge before departing at the end of last season.
Chelsea offered him a two-year deal to stay in west London, but Willian pushed for a three-year extension to his contract.
In the end the two parties were not able to agree terms, and the winger signed for Arsenal as a free agent.
The 32-year-old got off to an excellent start by providing two assists in a 3-0 victory over Fulham on the opening day of the season.
However, Willian has struggled since then and has come in for criticism among the club’s supporters.
Many have also questioned the logic of handing a three-year contract to a player who will turn 33 in August.
And the Brazilian has now admitted that his first choice last summer was to remain at Chelsea.
“It was difficult to make that decision because the rivalry between the two clubs is very big,” he told UOL Esporte.
“It was well thought out... talking to my wife and even the agent many times.
“I didn't leave the club with a fight, I left the doors open. Everyone knew the conditions, I really wanted to stay.
“We ended up not finding an agreement, I ended up asking for three years, Chelsea wanted to give two, and everyone knows this story. That's why I ended up leaving.
“One of the things that made me decide to go to Arsenal was really the various conversations I had with Mikel Arteta, with Edu too.
“They convinced me that I'd be a very important player in the squad.
“They wanted to change the philosophy of the club, to make it possible for Arsenal to fight again in the Premier League, to play in the Champions League again.”
Arsenal return to top-flight action when they face Leicester on Sunday.
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