Arsenal defender David Luiz says he left Chelsea to escape his comfort zone following a "real honest conversation" with Frank Lampard.
The Brazilian moved across London for a reported £8million fee on deadline day.
His guaranteed starting spot under Maurizio Sarri became less secure with Lampard's return to Stamford Bridge and the former teammates agreed to part ways.
Arsenal boss Unai Emery looks to have bigger plans in mind for the 32-year-old and handed him a debut in Saturday's 2-1 home win over Burnley.
"I am a guy with ambition and that is why I moved," David Luiz said.
"This is what gives me oxygen and gives me motivation and also to really enjoy this moment.
"But I like a new challenge and new things in my life.
"I am trying to be first honest with my heart and honest in the way that I try to feel new things."
After two seasons at Paris Saint-Germain, David Luiz returned to Chelsea for a second stint in 2016 and went on to win the Premier League, the FA Cup and the Europa League.
"Everyone knows I was so happy at Chelsea and won many trophies there," he said.
"I had a real honest conversation with Lamps, and Lamps had different ideas for his plans for the year.
"So the best way for me to respect the club where I can was to move on and try to do a new challenge and give him the opportunity to do his job.
"I am so happy here [at Arsenal] as since the first day I felt welcome.
"This is a big club and I want to be here and see it shine – on the pitch and outside."
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