New York — Seven-time Grand Slam champion Venus Williams became the oldest semifinalist in US Open history at age 37 on Tuesday by defeating two-time Wimbledon champion Petra Kvitova 6-3 3-6 7-6 (7/2).
Ninth seed Williams, seeking her third US Open crown, advanced to a Thursday match-up against 83rd-ranked compatriot Sloane Stephens for a spot in Saturday’s final.
"I’m so fortunate to have won that match. It came down to the wire," Williams said. "I try to tell myself enjoy the competition, enjoy the battle and I think I was able to do that."
Stephens, who missed 11 months with a left foot injury before returning at Wimbledon, matched her best Grand Slam showing by outlasting Latvian 16th seed Anastasija Sevastova 6-3 3-6 7-6 (7/4).
"This is just incredible," Stephens said. "When I started my comeback at Wimbledon I could never have dreamed of having ... these results."
Stephens has won 13 of her past 15 matches and matched her 2013 Australian Open semifinal run for best Slam effort.
Williams, who improved to 2-4 all-time against the Czech 13th seed on Tuesday, will return to the world top five for the first time since January 2011, a span that saw her diagnosed with the energy-sapping disease Sjogren’s Syndrome.
Williams, the oldest Slam semifinalist since Martina Navratilova at Wimbledon in 1994, won the 2000 and 2001 US crowns.
She was runner-up this year at Wimbledon and the Australian Open and could reach three Slam finals in a year for the first time since 2002.
Kvitova battled back from a five-month absence after a knife-wielding home intruder injured her left hand in December 2016.
"I’m glad I’m still able to compete on the high level against the top players which I hope will give me some confidence to continue to play well," she said.
If Americans Madison Keys and CoCo Vandeweghe win on Wednesday, they will produce the first all-American US Open semifinals since 1981.
"I hope there are four Americans in the semifinals," Stephens said.
Sevastova, who matched her best Major run from 2016 at New York by ousting Maria Sharapova to reach the last eight, led 3-1 in the third set before Stephens rallied.
"I just told myself to keep fighting and stay consistent," Stephens said. "I knew if I just stick with it and stayed in every point I’d have my opportunity."
In the tie-break, Stephens took four of the last five points, three on Sevastova errors before a down-the-line backhand winner ensured her victory to reach the top 35 in next week’s rankings.
Sevastova admitted nerves got to her in the tie-break, saying: "It’s normal. You play for the semifinals of the US Open. I’m not a robot. Sorry."