Literally on her last leg, Pironkova gives Williams an exciting challenge

Leaving it all out there 😵

Williams & Pironkova are giving everything they have. #USOpen pic.twitter.com/2I5uXj9oL7

— US Open Tennis (@usopen) September 9, 2020

Her thigh, which had been wrapped for days, was still troubling her. She was exhausted. It wasn't a good day for Tsvetana Pironkova to play anyone, much less Serena Williams.When I saw the Bulgarian player too hampered to hit her impressive serve in the round of 16, and then limp to the net for the "handshake," I thought it might be over for her, barring a physio miracle. I was right.

In the first set of her quarterfinal match against Williams, Pironkova was still fresh enough to bring her signature trouble to her opponent--slicing the forehand, changing pace, and garnering some amazing service stats. She won that set, but two things happened in the second set--Pironkova started to show all the wear and tear her body (especially her thigh) had accumulated through the tournament, and Williams rose--big time--to the occasion.

SHE'S BACK IN A BIG WAY. 😄 💪@vika7 scores her ticket to her first Grand Slam semifinal since 2013, dropping only 1 game against Elise Mertens. #USOpen pic.twitter.com/5IPbnMAB7t

— Tennis Channel (@TennisChannel) September 10, 2020

Serena Williams won the match, 4-6, 6-3, 6-2. She hit 20 aces. She's now into the semifinals, in which she will face off against a familiar opponent, Victoria Azarenka, who defeated Elise Mertens 6-1, 6-, in the second quarterfinal of the day. Mertens failed to hold serve even once. For Azaarenka, who has been through so much in the last few years--and who has always been strangely snake-bitten--this tournament has been a revelation. The Vika of years ago has emerged, and she is as dangerous as ever. She also has a better serve.

The other semifinal will feature Jennifer Brady and Naomi Osaka, and there aren't enough gourmet additives in existence to toss into that popcorn. Brady has yet to drop a set (and hasn't dropped that many games), and Osaka has looked like the problem-solver supreme. 

Wheelchair tennis singles play begans tomorrow, and top seed Diede De Groot, who has sustained a slump (for her) of late, will begin her U.S. Open campaign against Jordanne Whiley. 

3rd seeds Nicole Melichar and Xu Yifan advanced to the doubles final today when they defeated Asia Muhammed and Taylor Townsend 6-4, 3-6, 7-6 (7). Their opponents will be Laura Siegemund and Vera Zvonareva.