NEW YORK (AP) The Latest on the U.S. Open, the year's last Grand Slam tennis tournament (all times local):
Madison Keys grabbed the last four games to eliminate No. 4-seeded Elina Svitolina 7-6 (2), 1-6, 6-4 and give the United States four women in the U.S. Open quarterfinals for the first time in 15 years.
The 15th-seeded Keys joins Americans Venus Williams, CoCo Vandeweghe and Sloane Stephens in the final eight at Flushing Meadows.
It's also the first quarterfinal appearance in New York for Keys.
Next for Keys is a match against 418th-ranked qualifier Kaia Kanepi of Estonia.
No. 4 seed Elina Svitolina has come back to take the second set and force 15th-seeded Madison Keys to a third at the U.S. Open.
Svitolina needed just 24 minutes to grab the second set of their fourth-round match by a 6-1 score. Keys claimed the opener 7-6 (2).
Madison Keys has taken the opening set of her fourth-round U.S. Open match against No. 4-seeded Elina Svitolina by a 7-6 (2) score.
The 15th-seeded Keys finished the set with a 19-4 edge in winners.
Keys is trying to reach the quarterfinals at Flushing Meadows for the first time in her career.
She lost in the fourth round each of the past two years.
Roger Federer took a medical timeout after the second set and otherwise showed no signs of trouble in a 6-4, 6-2, 7-5 victory over No. 33 seed Philipp Kohlschreiber to reach the U.S. Open quarterfinals.
Federer did not face a break point and won in straight sets for the second time in a row after being pushed to five sets in each of the first two rounds. He improved to 12-0 for his career against Kohlschreiber.
During the on-court interview at Arthur Ashe Stadium afterward, Federer said with a laugh at the break before the third set Monday night was because he ''just needed a bit of a rub on my back or my bottom and I didn't want to do it on court.''
The No. 3-seeded Federer will face Juan Martin del Potro in the quarterfinals. They met in the 2009 U.S. Open final, when del Potro won his only Grand Slam title and ended Federer's run of five championships in a row in New York.
Juan Martin del Potro saved two match points and erased a two-set deficit to come all the way back to beat No. 6-seeded Dominic Thiem 1-6, 2-6, 6-1, 7-6 (1), 6-4 and reach the U.S. Open quarterfinals.
Del Potro, the 2009 champion at Flushing Meadows, used a pair of aces to erase match points for Thiem at 6-5 in the fourth set, then dominating the ensuing tiebreaker.
In the fifth set, as the match stretched beyond 3 1/2 hours, del Potro broke in the last game when Thiem double-faulted.
Here's how close it was: Thiem actually won more points, 141-139.
Juan Martin del Potro went from looking down-and-out at the U.S. Open to forcing a fifth set against No. 6-seeded Dominic Thiem.
Del Potro, the 2009 champion at Flushing Meadows, dropped the opening two sets of the fourth-round match.
After taking the third set, he then trailed 5-2 in the fourth and had to save two match points. But he took that set in a tiebreaker.
The U.S. Tennis Association says it has donated $500,000 to Hurricane Harvey relief efforts - and will add more from fundraising at the U.S. Open, with the help of five-time champion Jimmy Connors.
Future funds will be used to help storm-affected tennis facilities.
The USTA says it will match donations encouraged from spectators at the U.S. Open by Connors, who is raising money at the tournament site by signing autographs and posing for photos with fans.
Kaia Kanepi is the first qualifier in 36 years to reach the U.S. Open women's quarterfinals.
The 32-year-old Estonian is ranked 418th after missing much of the past two years with problems in the soles of both feet and a virus known as a precursor to mononucleosis.
No one has advanced to the quarterfinals at Flushing Meadows with such a low ranking, although five women - including 2009 champion Kim Clijsters - did so while unranked entirely. That includes Barbara Gerken, who made it that far in 1981 as a qualifier.
Kanepi was able to get into the qualifying event by virtue of a protected ranking.
This is her sixth trip to a Grand Slam quarterfinal, but first since Wimbledon in 2013. She is 0-5 in that round previously.
CoCo Vandeweghe reached her first U.S. Open quarterfinal by beating Lucie Safarova 6-4, 7-6 (2).
The 20th-seeded Vandeweghe is into the round of eight at a Grand Slam tournament for the third time this season. She lost at that stage at Wimbledon in July, after making it to the semifinals at the Australian Open in January.
Vandeweghe is the third American woman into the quarterfinals at Flushing Meadows this year, joining Venus Williams and Sloane Stephens, who won their fourth-round matches a day earlier. Madison Keys could raise the total to four by winning her fourth-rounder later Monday.
Andrey Rublev beat No. 9 seed David Goffin 7-5, 7-6 (5), 6-3 to become, at 19, the youngest male U.S. Open quarterfinalist since Andy Roddick reached the round in 2001.
Rublev next faces top-seeded Rafael Nadal, who beat Alexandr Dolgopolov 6-2, 6-4, 6-1 earlier Monday.
The Russian Rublev entered the top 50 for first time in late July.
Rafael Nadal easily reached the U.S. Open quarterfinals, beating Alexandr Dolgopolov 6-2, 6-4, 6-1.
The No. 1 seed is back into the quarters in Flushing Meadows for the first time since 2013, when he won his second of two U.S. Open titles.
He broke serve six times and needed just 1 hour, 41 minutes to finish off his unseeded opponent and set up a matchup against either No. 9 seed David Goffin or unseeded Andrey Rublev.
Rafael Nadal is a set away from the U.S. Open quarterfinals.
The No. 1 seed leads Alexandr Dolgopolov 6-2, 6-4 after a little more than an hour in a fourth-round match.
Though Dolgopolov is unseeded, he had won two of the last three meetings with Nadal.
Top-seeded Rafael Nadal has taken the first set 6-2 from Alexandr Dolgopolov in their fourth-round match at Arthur Ashe Stadium.
Nadal is trying for his first U.S. Open quarterfinal appearance since winning the Grand Slam tournament in 2013.
Karolina Pliskova powered her way into the U.S. Open women's quarterfinals, overwhelming American Jennifer Brady 6-1, 6-0 in just 47 minutes.
Two days after fighting off a match point to advance, the No. 1 seed won 22 of 24 points on her first serve and broke her unseeded opponent's serve six times.
The U.S. Open runner-up last year, Pliskova advanced to face either No. 20 CoCo Vandeweghe or unseeded Lucie Safarova.
She raced to a 4-0 lead and never let Brady get into the match in a much better performance than Saturday, when she struggled past No. 27 Zhang Shuai 3-6, 7-5, 6-4.
Karolina Pliskova has won the first set 6-1 against American Jennifer Brady, a much better start for the women's No. 1 seed than in her last match.
Pliskova raced to a 4-0 lead in the fourth-round match and closed the set in just 26 minutes after Brady double-faulted on set point.
Pliskova also played the first match on Arthur Ashe Stadium on Saturday. She dropped the first set and had to fight off a match point in the second before rallying to beat No. 27 Zhang Shuai 3-6, 7-5, 6-4.
Former champions Roger Federer, Rafael Nadal and Juan Martin del Potro try to reach the U.S. Open quarterfinals, while top-seeded Karolina Pliskova and No. 4 Elina Svitolina face American opponents in women's fourth-round matches.
Federer brings an 11-0 record against No. 33 seed Philipp Kohlschreiber into their night matchup. The top-seeded Nadal faces Alexandr Dolgopolov on Monday afternoon.
The No. 24 seed del Potro faces sixth-seeded Dominic Thiem, with the winner getting Federer if the five-time champion can improve his 31-1 record in night matches at Arthur Ashe Stadium.
Pliskova opens the Labor Day schedule against unseeded Jennifer Brady. Svitolina meets No. 15 seed Madison Keys in the nightcap.
Keys, Brady and No. 20 seed CoCo Vandeweghe are trying to join fellow Americans Venus Williams and Sloane Stephens into the women's quarters.
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