The Brazil international has developed into a key man for the Blues ever since arriving at Stamford Bridge in 2013, although there were rumours aplenty that the 30-year-old would be embarking on a new challenge this season.
"I love to live here, my family love to live in London, I love to play for Chelsea, everything is amazing," he said. "I have been here for five years and I hope to stay more. Everything is perfect. My family don't want to leave."
According to Sky Sports, the Blaugrana made three offers for Willian during the summer, and all three, the highest of which was said to be in excess of £55 million, were rejected.
It was also reported by Steve Bates of the Sunday Mirror that United were ready to offer Anthony Martial to Chelsea in an exchange deal involving Willian. The Blues were said to value their No. 22 at £75 million.
In the end, Willian remained at Chelsea and has been playing a part under manager Maurizio Sarri. So far he has been in competition for a spot on the right flank with Pedro, with Eden Hazard wreaking havoc on the left.
It's in the UEFA Europa League where Willian has been at his best this season and he starred again on Thursday as the Blues overcame BATE Borisov 3-0. Per Scouted Football, this season he's been one of the most creative players in the competition:
Despite his work rate and versatility, opinion has long been split among Chelsea supporters when it comes to Willian. Some eyebrows were certainly raised when a reported £55 million was turned down for him in the summer.
The Brazilian can look exceptional when he is at his best, as he has the pace and ingenuity to ghost past players and find passes. However, there are also occasions when he makes rash decisions in the final third.
Per Liam Twomey of ESPN FC, there are other Chelsea forwards who appear much more at ease when put in on goal:
Brazilian football journalist Fernando Duarte noted that Willian does seem to get unlucky a lot too:
Even so, Sarri will surely be pleased Chelsea have kept hold of Willian, as he is a brilliant option to have on the right and someone who is always involved in the game due to his excellent application.
Chelsea supporters would love to see Willian become more productive in front of goal now he's in his 30s, and you sense another ruthless finisher will be needed if they're to challenge for the title this season. The winger's best total in the Premier League since moving to England is only eight.