rest on (one's) laurels

Translations
почивать на лаврах
After winning the championship, the team decided to rest on their laurels and didn't train as hard.
После победы в чемпионате команда решила почивать на лаврах и не тренировалась так усердно.
Definitions
To stop putting in effort or to become complacent after achieving success, relying on past accomplishments instead of continuing to strive for improvement or new achievements.
Words
laurel

noun
лавр
rest

verb
отдыхать
rest on

verb
опираться на