New York: Hard-hitting Czech Karolina Pliskova toppled two-time champion Venus Williams 4-6, 6-4, 7-6 (7/3) on Monday to reach her first Grand Slam quarter-final at the US Open.
Pliskova, who had never before made it past the third round of a major in 17 prior attempts, saved a match point en route to a victory which scuppered a possible semi-final clash between Williams and her sister Serena.
The 36-year-old Williams was vying to become the oldest woman to reach the US Open quarters in the Open Era.
But the in-form Czech -- who shocked world number two Angelique Kerber in the final at Cincinnati in August -- settled her own late nerves to pull off the upset in front of a partisan Arthur Ashe stadium crowd.
"I was prepared that I'm going to play Venus, it's going to be tough because people will be cheering for her," Pliskova said.
Williams was philosophical about her failure to convert a match point against Pliskova's serve in the 10th game of the third.
"She had a great serve," Williams said. "She hit another great shot and I still played a great defensive shot. I did the best I could on that.
"Whenever you have a match point on someone else's serve, it's a little bit of an asterisk. I really have no regrets on that."
Pliskova then broke Williams for a 6-5 lead -- with the help of a favorable net cord bounce.
Serving for the match and up 40-0, however, Pliskova couldn't close it out. A double fault followed by four strong points from Williams sent it to the tiebreaker.
"To be honest it was very difficult after I lost my serve for six-all," Pliskova admitted. "She played a very good game."
There was one last agonizing moment for Pliskova, who appeared to have won the decider with a ball that was ruled out on a challenge.
But she was able to celebrate for real when Williams sent a service return long on the next point.
Halep eases through
Simona Halep punched her ticket to the US Open quarter-finals on Monday, where the fifth-ranked Romanian will likely find world number one Serena Williams waiting.
Halep, a former French Open finalist who has won three WTA titles in 2016, defeated Spain's Carla Suarez Navarro 6-2, 7-5 -- edging ahead in a rivalry that had seen them split their previous 10 matches 5-5.
"I just gave everything I had," said Halep, who sailed through the first set and gained an early break in the second before Suarez put the brakes on.
Serving for the match at 5-4, Halep was broken, but she broke back immediately and made no mistake with her second chance.
"I'm really happy I could win this match," said Halep, who was already looking forward to a probably clash with Williams.
"The next round will be a very tough one, so I want to enjoy this victory today," she said.
Williams, gunning for a seventh US Open title and 23rd Grand Slam crown -- both of which would be Open Era records -- was the star attraction Monday taking on 52nd-ranked Yaroslava Shvedova.
Williams has won all four of her prior meetings with the Kazakh and even though she's still receiving treatment on a balky right shoulder she has reached the round of 16 without dropping a set.
A victory over Shvedova would not only put her into the last eight, it would take her to 308 Grand slam match wins -- past Roger Federer for the most by anyone in the Open Era.
Although she seems to rack up a Grand Slam record any time she steps on the court, Williams' reign atop the world rankings is under pressure, with quarter-finalist Angelique Kerber now poised to topple her if the American doesn't reach the final.
Fourth-seeded Agnieszka Radwanska, who also has an outside chance of seizing the number one ranking, faces a tricky battle for a quarter-final berth against Ana Konjuh.
Poland's Radwanska had to save three match points to get past the 18-year-old Croatian in the second-round at Wimbledon this year.
In the fourth round of a Grand Slam for the first time, Konjuh will be out to prevent Radwanska from advancing in the only major in which she has never reached the quarters.
The other quarter-finals have already been set, with two-time runner-up Caroline Wozniacki to face Latvia's Anastasija Sevastova in a battle of comeback kids and Kerber taking on seventh-seeded Roberta Vinci, the Italian who shocked Serena last year en route to the 2015 final, where she was beaten by compatriot Flavia Pennetta.