Marcos Alonso has signed an extension with Chelsea through 2023.
"I am so happy to stay here longer and to keep playing for one of the best teams in the world," Alonso told Chelsea's website. "It's been a very good two seasons and I am looking forward to more."
Alonso was a relatively unheralded signing for Chelsea, in a £24 million deal from Fiorentina, in August 2016 but has established himself as a key contributor, operating effectively at left wing-back under Antonio Conte and transitioning well to the left of a back four since Maurizio Sarri's arrival.