Willian has apologised to Arsenal fans for a disappointing spell at the club as he rejoins Corinthians.
The Brazil midfielder completed a move back to his home country after Arsenal terminated his contract on Monday.
"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," the 33-year-old wrote on Instagram.
"Unfortunately it didn't happen for me at Arsenal and I am sorry about that."
Willian arrived on a free transfer in August 2020 after leaving Chelsea, signing a three-year deal reportedly worth more than £200,000 a week.