The Swans are unbeaten in three meetings against this season; the league meeting at the Liberty Stadium ended 1-1, while the Welsh side secured a 2-0 aggregate victory in the League Cup semi-finals.
Flores said: "I don't know if they were our best performances of the season but obviously to keep Chelsea to zero in two games is an achievement.
"But it is not just about me and Ashley Williams - our whole defence was good over those two games and has been throughout the season.
"Ben Davies is young and new to the Premier League but he has done well and is improving all the time, and Angel Rangel has been here for many years and is very good.
"We have two good goalkeepers in Michel Vorm and Gerhard Tremmel and as a team we work hard in defence, including the strikers and midfielders."
The 26-year-old Spaniard - who played under Michael Laudrup at Mallorca - is happy with the progress he has made in his debut season in the Premier League.
"I'm a young player, but I've played in Spain, Italy and, this year, the Premier League," he added.
"I learned after the red card at Sunderland to control my aggression, that the Premier League is different.
"It's normal for a player in a new league to make a mistake and to learn from it and I think I have."