Serena Williams welcomed Roger Federer to the tennis “retirement club” on Thursday, saying she has always admired and looked up to the Swiss legend. Federer, a 20-time Grand Slam champion, said on Thursday he would retire after playing next week in London at the Laver Cup.

Among those sending congratulatory messages to the 41-year-old icon for his tremendous career was 23-time Grand Slam winner Williams, who said she was “evolving” away from tennis, with last week’s US Open expected to be her final tournament.