The Blues take on Liverpool at Wembley in the final (14.05.22) and Werner is convinced that they can upset the odds against the quadruple-chasing Reds by taking inspiration from their Champions League victory against Manchester City last season.
The German striker said: "The FA Cup final is a bit similar to the Champions League final last year.
"In the two years I've been here, we've always had good games against Liverpool. We've never lost in 90 minutes. They always have problems with us, so maybe the underdog role suits us."
Chelsea lost the League Cup final to the same opponents on penalties earlier this year and Werner is aiming to end the season with silverware.
He told Standard Sport: "It is one of the biggest cups in Europe. We want to win it. Okay, in the league, it was not possible to follow the others, and in the Champions League we had one bad game that put us out."
The Blues have lost two FA Cup finals in a row - to Arsenal in 2020 and then Leicester in 2021 - and Werner doesn't want to make unwanted cup history.
He said: "We lost the last two years in the FA Cup final - that is also a big point why we want to win. When you are three years in a row in the final and lose it three times, that would not be the best record that you can put into the history of the FA Cup."