Willian has admitted he found it hard to accept not winning at Arsenal after his departure was confirmed.
The Brazilian signed a three-year deal last summer having joined on a free from Chelsea.
However he has struggled to produce his best form with criticism regularly coming his way after he signed a deal worth north of £200,000-a-week.
In his debut year at the Emirates he managed just one goal in 37 appearances.
Willian opted to rip up the remaining two years of his contract, worth £20m, and return to his homeland with Corinthians.
Prior to his move across London the 32-year-old had won two league titles, an FA Cup and the Europa League.
He penned a farewell message thanking the club for their support, but underlining his regret at how the move had materialised.
“I would like to thank Arsenal for the opportunity they have given to me and for the warm welcome received by everybody at the club,” he wrote.
“Unfortunately things on the pitch didn’t go the way we had planned ad hoped, I received a lot of criticism especially from some members of the press that I had come here for financial reasons.
“I hope with my actions today explain to those people and they now understand that was not the case.
“I hope it teaches some people that they should not be so quick to pass judgement and create bad environments to make themselves important though I accept that’s part of the game.
“All my career I have done everything to be the best I can be. I always want to win and I find it hard to accept not doing so.
“Unfortunately it didn’t happen for me at Arsenal and I am sorry about that.
“I came to England in 2013 and I have enjoyed every minute of my time here. I want to thank everyone who has helped me along the way to play in this wonderful league that is full of heart and spirit.”
Willian was yet to feature for Arsenal in their opening three games, all of which they’ve lost.
Mikel Arteta has presided over the club’s worst start to the season since the 1950s with pressure mounting on the Spaniard.
Arsenal’s poor recruitment saw them finish eighth last term and, despite spending over £100m on new players, the Gunners again look set to struggle with their transfer business heavily criticised.
Ainsley Maitland-Niles and Reiss Nelson could follow Willian out the exit door with both players attracting interest.