Willian concedes his initial months at Arsenal were the "worst time" of his career.
The winger crossed London in the summer and joined the Gunners on a free from Chelsea.
He penned a lucrative three-year deal despite being 32 which raised eyebrows and when his performances declined criticism was quick to come his way.
Mikel Arteta shuffled the pack at Arsenal which meant Willian was forced to sit out in certain games - a period he called the "worst time that I think I lived as a professional".
Willian has begun to rediscover his form of late and assisted four times in his last five games.
The Brazilian believes his best football is on the horizon, but has opened up on a difficult season.
"It really was a very difficult start, apart from that first game against Fulham, where I had a good performance, I managed to make a good game," he said in an interview with ESPN Brazil.
"Even after that game there were some games that we won, I even had a good game, but then we ended up getting a bad streak.
"I also got a bad streak and I think my worst professional time to date, since I went up at Corinthians and was sold to Ukraine, then I arrived at Chelsea, without a doubt.
"This phase that passed now was the worst time that I think I lived as a professional.
"Of course, when you live in a difficult moment, you get really upset and try to find solutions, a way to improve, try to help the team.
"That's what I've been doing all this time, I never stopped training, to work, to dedicate myself as much as possible.
"It took a little while to leave, but lately in the last games I've been playing well again, standing out with assists, playing well.
"So I'm happy to be back to find my good football."
