Chelsea are a club where proving mettle is no easy feat for a player. Since they always compete for titles, maintaining a position in Chelsea's starting line-up over a period of time is demanding. If there is a better alternative available in the market, Chelsea will instantly replace an underperforming player often without considering past performances.Not all Chelsea players have wilted under that pressureA player's legacy at Chelsea is often measured by longevity as well as the amount of silverware the player collects at Stamford Bridge. Chelsea legends such as Frank Lampard, John Terry, Petr Cech and Didier Drogba have all done it successfully in the past.However, the following list considers the aforementioned factors to rank foreign players to have played for Chelsea solely over the last decade (2011-2021).Honorable mentions: Nemanja Matic and Diego Costa for their memorable spells at Chelsea.#5 WillianChelsea FC v Arsenal FC - Premier LeagueWillian is a player who often divides Chelsea's fan base. On paper, he's had an excellent time at Stamford Bridge. Willian joined Chelsea from Anzhi Makhachkala in 2013. Seven years and 339 appearances later, the Brazilian winger joined London rivals Arsenal after his Chelsea contract expired in 2020.Willian recorded 63 goals and 62 assists during his time in blue. The 32-year-old is fondly remembered by Chelsea fans for the spectacular manner in which he rejected Spurs and joined the Blues at the eleventh hour.A true Chelsea great. Thank you, @willianborges88! 💙 pic.twitter.com/JT8Hsh69Tg— Chelsea FC (@ChelseaFC) August 10, 2020Willian's best time in a Chelsea shirt came in the 2015-16 campaign when Eden Hazard went through a rough patch. Unfortunately, it was during a season in which Chelsea struggled, with Jose Mourinho getting sacked and Guus Hiddink arriving on an interim basis to replace him.The winger won two Premier League titles, one FA Cup, one League Cup and one Europa League during his time at Chelsea.#4 Cesc FabregasChelsea v PAOK - UEFA Europa League - Group LCesc Fabregas was a Chelsea player for just four-and-a-half years but made a lasting impact. His chant of 'Fabregas is magic' could not have been more apt. Fabregas mesmerized the crowd with his extraordinary vision every time he took to the pitch.Fabregas 🤝 Costa What a partnership they had man. pic.twitter.com/M1nOJcchFg— Conn (@ConnCFC) August 3, 2021The Spanish midfielder made 198 appearances for Chelsea, scoring 22 goals and notching up 57 assists. Despite making over 300 appearances for London rivals Arsenal, Fabregas always looks back at his time at Chelsea with love.He will always be remembered for his lethal partnership with Diego Costa, who terrorized defenses alongside him en route to two Premier League titles. Furthermore, Fabregas won the FA Cup and League Cup, while also featuring in the group stages of the Europa League in 2018-19, which Chelsea won under Maurizio Sarri.