When the @TennisTV Twitter account asked its followers to pick one of eight tennis-related options, 20-time Grand Slam champion Roger Federer's choice was easy: to bring back his favorite retired player.

Turned out that this meant a legion of beloved former champions - including a selection of WTA Legends to whom the former ATP World No.1 paid tribute. Naturally, he began with Swiss compatriot Martina Hingis, with whom Federer won the 2001 Hopman Cup: "She was amazing, loved watching her play. Tennis IQ was off the charts," he wrote.

Another Federer favorite was 22-time Grand Slam champion Stefanie Graf. "Watched her for hours, mesmerizing forehand, footwork and attitude," he rhapsodized. The 38-year-old also agreed with a fan who praised nine-time major winner Monica Seles as "amazing", and gave WTA founder and lifelong pioneer Billie Jean King her due as a "trailblazer" - as well as 18-time Grand Slam champion Chris Evert.

Gabriela Sabatini, Monica Seles, Roger Federer, Grigor Dimitrov - World Tennis Day Reception 2015

Gabriela Sabatini, Monica Seles, Roger Federer and Grigor Dimitrov at the 2015 World Tennis Day reception in New York.

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Federer also remembered Argentina's most accomplished player Gabriela Sabatini, the 1990 US Open champion, as both the "nicest person" and a "wonderful player". And while he described Martina Navratilova as "easy Top 3 ever, men and women", there was a personal reason for the 18-time major winner to be in his heart as well: "Thanks to Martina I met [wife] Mirka," he revealed.

Meanwhile, World No.10 Naomi Osaka joined a pantheon of pop culture icons including Beyoncé, Lady Gaga, Megan Rapinoe and David Beckham in The One World: Together at Home, a streaming event set up by the World Health Organization and Global Citizen to encourage philanthropists and companies to contribute to the WHOI's Covid-19 Solidarity Response Fund. "I wanted to take this opportunity to thank all the healthcare workers and people on the frontlines who are helping us through this pandemic," said Osaka, before reading out letters of appreciation from fans around the world.

Former World No.55 and current media commentator Sam Smith has also been stepping up - literally. The Briton, who reached the fourth round of Wimbledon 1998, has set herself a goal of running up and down the stairs outside her home - carrying 5kg of books on her back - to raise money for food banks in the UK.

For 2015 US Open finalist Roberta Vinci, lockdown has been an opportunity to get some DIY done at home.

Elsewhere, WTA stars are finding that the kitchen is where they're at their most creative. Former World No.1 Caroline Wozniacki has perfected a delectable-looking layered red velvet cake - but Acapulco champion Heather Watson has been using her cupboard essentials for less traditional purposes, filming a TikTok "DJ set" from her kitchen with spices and seasonings as her decks.