Serena Williams
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Although Serena Williams is retiring soon, the 23-time Grand Slam champion still has "a little bit left" in the tank as she continues her 2022 US Open run. Williams advanced to the third round after taking down world No. 2 Annett Kontaveit in Wednesday's second round, which means fans are rushing to get tickets to see the veteran compete at least one more time. 

According to StubHub, US Open ticket sales have increased by more than 20% since her win over Kontaveit on Aug. 31. Tickets on the website for her Friday night match against Ajla Tomljanovac start at $431 each. That ticket is also good to watch No. 1 Daniil Medvedev take on Wu Yibing after the Williams vs. Tomljanovac match.

"Serena Williams' matches are the hottest ticket in sports right now, as fans flock to watch the star advance – sales on StubHub for her Friday night session have doubled overnight," said Adam Budelli, a spokesperson for StubHub. "Demand on StubHub for this year's US Open is tracking to soon surpass the entirety of sales for last year's tournament, with nearly a third of the overall sales driven by the opportunity to watch Serena make her final run."

Each of Williams' two singles matches at this year's US Open have set new attendance records for the tournament. Her first-round matchup against Danka Kovinic drew 29,402 fans, and two days later 29,959 fans came to see Williams take on Kontaveit in the second round. 

That's impressive, although not surprising, considering the top-ranked men's and women's players -- Medvedev and Iga Swiatek -- are still competing. Other stars still in the 2022 US Open include Rafael Nadal, Nick Kyrgios and Coco Gauff. Venus Williams was competing in the tournament too, but she was eliminated in the first round. The two Williams sisters played doubles together on Thursday night, eventually falling to the Czech duo of Linda Nosková and Lucie Hradecká.

Williams, unseeded at this year's tournament, will be taking on Tomljanovac on Friday at 7 p.m. ET at Arthur Ashe Stadium. Her victory against Kontaveit was considered an upset, but she is currently a favorite in her third-round matchup.

Click here for everything you need to know about the 2022 US Open, including scores, schedules and how to watch.