Serena Williams Turns Back Time at Australian Open

Sabalenka, a nine-time winner on the WTA Tour, and Swiatek, the reigning French Open champion, are the latest in a long string of polished phenoms threaded through Williams’s career. One of the biggest stars to emerge, Naomi Osaka, saved two match points to beat Garbiñe Muguruza on Sunday. Still, from Jennifer Capriati and Monica Seles to Maria Sharapova and Sloane Stephens, Williams has watched many young talents come and go and, on occasion, stray far from tennis.

A sport with a history of suffocating its young has not stifled Williams, a 23-time Grand Slam champion in singles whose love for the game seems to have deepened over time. Against Sabalenka, she studied a page of written notes during changeovers as if she were back in high school. She fiddled with her “Queen” necklace. She dug balls out of the corners and ran from side to side as if she were on a school blacktop at recess.

Darren Cahill, one of Halep’s coaches, described Williams’s movement as the best he had seen from her “in a long, long time” and said, “If you can stay in more points and get more balls back, stay alive, then she’s got the power to turn those points around.”

What Williams is doing is also inconceivable to the younger Americans, three of whom have followed her into the second week. Marveled, one of the three, the 28-year-old Shelby Rogers: “What she’s been able to accomplish is absolutely incredible because some days I wake up now and I’m like, ‘OK, I’m not 21 anymore.’”

Williams’s serve usually allows her to win her share of easy points. But against Sabalenka, her main weapon continually misfired. Williams put 52 percent of her first serves in play and recorded eight double faults, including one in the fifth game of the third set, which gave Sabalenka two break points.