The tricky winger came off the bench in their 4-1 win against Arsenal, as the Blues achieved their 16th major trophy since Roman Abramovich took over the club in 2004 to remain English football's most successful team in that period.
The joint-leading assist maker in this season's competition has been playing under a cloud of constant speculation regarding Maurizio Sarri's future, as the boss struggled to win over both fans and pundits.
However, speaking after his side destroyed their London rivals in the final in Baku on Wednesday night, the winger says the players simply block it out and, after achieving cup success alongside a top-four Premier League finish, thinks the group were underestimated by some this season.
“We don’t listen in this situation, we just focus on our training, on the game. We leave this part for the club to resolve and we have to focus on the game,” Willian said about Sarri before summing up his side's campaign.
"I think that we are underestimated. I think so. A lot of people, they think Chelsea have no chance to win anything this season because they don’t play well or something like this, but today we win this important trophy.
"Now we have to enjoy the holidays and prepare for next season. Chelsea want to win titles. Every year Chelsea fight for titles - something important. This year was the same. To finish the season in this way is amazing. I think we did a great job.
“I think there were a lot of ups and downs. At the end we took the third position in the Premier League, we went to the Carabao Cup final and now we win the Europa League final, so if you think about that, you can say it was good. Now it’s time to enjoy.”
Sarri will now conduct post-season talks to consider whether he will continue in his current role or leave Stamford Bridge. Juventus director Andrea Agnelli was in attendance at the Baku Olympic Stadium and he can secure Sarri by buying out his contract for £5 million ($6.3m).
Eden Hazard also said that he believes the final, where he scored twice, will be his last game for the club. Willian is close friends with the Belgian superstar but he thinks that there will be life after Hazard at Chelsea, as Real Madrid target a summer transfer valued at around £100m.
“Of course, it is difficult to lose players like him," Willian continued. "But if he goes, Chelsea will do everything to buy or I think here we have players with quality who can continue the job without him.
"He is a special player, a fantastic player, but Chelsea always is like this. The job will continue.”