The Brazilian moved to Stamford Bridge from Anzhi Makhachkala last month for a fee believed to be in the region of £30million.
Chelsea boss Jose Mourinho fought off competition from Premier League rivals Tottenham and Liverpool to land Willian's signature and add to his wealth of attacking options.
However, despite the size of his transfer fee, the 25-year-old expects a tough battle to force his way into Mourinho's starting XI due to the strength of competition provided by the likes of Eden Hazard, Oscar, Juan Mata and Andre Schurrle.
"I know that I haven't secured my spot here. I'll do my best to achieve that place, while respecting the other players. I'll train, play and do my best to get the trust of the manager and of the fans," he told Globo Esporte.
Speaking of his reasons for opting for Stamford Bridge ahead of White Hart Lane and Anfield, Willian explained that Chelsea's Brazilian contingent played their part, while the prospect of playing for Mourinho was also too good to miss.
"The Brazilians called me, especially David Luiz, who told me to come quickly. I was very happy to have them around and they will certainly help me a lot," he added.
"I wanted to play at Chelsea, even more so now with Jose Mourinho, who is the best at what he does."
