United States' Serena Williams makes a backhand return to Australia's Daria Gavrilova during a tuneup tournament ahead of the Australian Open tennis championships in Melbourne, Australia, Monday, Feb. 1, 2021. (AP Photo/Hamish Blair)MELBOURNE – Serena Williams found a silver lining in the delayed start to the Australian Open, the season-opening Grand Slam tournament that is starting three weeks later than usual because of the COVID-19 pandemic. Williams is playing in the Yarra Valley Classic, along with top-ranked Ash Barty and defending Australian Open champion Sofia Kenin. “So I definitely was pushing the limits, but I’m here.”Williams has been stalled on 23 major singles titles since the 2017 Australian Open, when she was two months pregnant with now-3-year-old daughter Olympia. AdFrances Tiafoe, an Australian Open quarterfinalist in 2019, lost to Corentin Moutet 3-6, 6-4, 6-4.