Serena Williams paid a glowing tribute to Roger Federer after the Swiss maestro announced his retirement from professional tennis on Thursday. Venus Williams then posted her younger sibling's message on her Instagram story, and revealed why she was envious of her sister.

Federer has been absent from the tour since August last year after undergoing a third knee surgery in a span of only 18 months. The 20-time men's singles Grand Slam champion has resumed training in recent weeks, and was hoping to return in the second-half of the 2022 season.

However, the Picasso of the Open Era, with his flawless forehand and elegant one-handed backhand, has decided to hang up his racket for good after 24 years on the ATP Tour. Federer said that the upcoming Laver Cup in London will be his last competitive outing.

Williams, who like Federer, is widely regarded as the Greatest of All Time (GOAT) in the women's game, welcomed the Swiss great into the retirement club. The American called time on her illustrious career after her outing at the 2022 US Open earlier this month.

"I have always looked up to you and admired you. Our paths were always so similar, so much the same. You inspired countless millions and millions of people - including me - and we will never forget. I applaud you and look forward to all that you do in the future. Welcome to the retirement club," Williams wrote on Instagram.

Almost immediately after Williams' tribute, older sister Venus shared it on her Instagram. The 42-year-old admitted, albeit jokingly, that she was jealous of Serena for having more pictures with Federer during her career.

Venus, who has shared the champions stage at Wimbledon with Federer on two occasions in 2005 and 2007, also paid tribute to the 41-year-old. The seven-time women's singles Grand Slam champion's message, however, was a short one, it read: "The greatest ever. Miss you already," alongside pictures of the two players with their Wimbledon winners' trophies.

Federer is now expected to arrive in London for his final competitive event - the Laver Cup - next week. The Swiss ace will team up with Big Three rivals Rafael Nadal and Novak Djokovic as part of Team Europe and take on Team World that includes US Open semifinalist Francis Tiafoe, and American Taylor Fritz.

Roger Federer
Roger Federer announced his retirement from tennis on September 15, 2022 after 24 years on the ATP Tour - AFP / Adrian DENNI