NEW YORK (AP) — The Latest on the U.S. Open, the last Grand Slam tournament of the year (all times local):

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11:52 p.m.

Roger Federer overcame a slow start, then a late lapse, and needed five sets to win a topsy-turvy first-round match at the U.S. Open against 19-year-old American Frances Tiafoe.

The No. 3-seeded Federer got broken in the first game and dropped the opening set, and then appeared to take control before letting a lead slip away. Eventually, he edged the 70th-ranked Tiafoe 4-6, 6-2, 6-1, 1-6, 6-4 by breaking serve in the last game.

It was Federer's 79th career victory at the U.S. Open, equaling Andre Agassi for second-most. Only Jimmy Connors has more, with 98.

Federer played under the closed roof at Arthur Ashe Stadium for the first time. He missed last year's tournament, when the retractable cover made its debut.

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11:15 p.m.

Roger Federer and 19-year-old American Frances Tiafoe are heading to a fifth set at the U.S. Open.

Tiafoe took the fourth set 6-1 to push the first-round match to the distance.

Tiafoe grabbed the opening set 6-4, before Federer took the next two 6-2, 6-1.

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10:50 p.m.

Roger Federer has won eight of nine games to take control of his first-round U.S. Open match against 19-year-old American Frances Tiafoe.

After dropping the opening set 6-4, Federer has taken the next two 6-2, 6-1.

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10:23 p.m.

Roger Federer has righted himself and evened his first-round U.S. Open match against 19-year-old American Frances Tiafoe at a set apiece.

Federer took the second set 6-2. Tiafoe grabbed the first 6-4.

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9:50 p.m.

Roger Federer has a deficit to deal with at the U.S. Open after surprisingly dropping the first set of his match against American teenager Frances Tiafoe by a 6-4 score.

The No. 3-seeded Federer started the first-round match poorly. He got broken in the opening game and made 18 unforced errors in the first set, which lasted 36 minutes.

Tiafoe is a 19-year-old who is from Maryland and now is based in Florida. He is ranked 70th and has never been past the second round at a Grand Slam tournament. Federer, 36, owns a record 19 major championships, including five at the U.S. Open.

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8:55 p.m.

Madison Keys moved into the U.S. Open's second round by beating Elise Mertens of Belgium 6-3, 7-6 (6) under the roof in Arthur Ashe Stadium.

The 15th-seeded Keys, who was born in Illinois and is based in Florida, had a bit of trouble closing things out against the 39th-ranked Mertens.

First, Keys was broken while serving for the match at 6-5 in the second set. In the ensuing tiebreaker, the American trailed 6-5, meaning Mertens was one point from forcing a third set. But Keys delivered a big forehand that forced a backhand error, starting a three-point run that ended her victory.

In all, Keys compiled a 32-9 edge in total winners.

She showed no signs of any lingering problems with her left wrist, which was operated on during the offseason, forcing her off the tour for the first two months of 2017. She had a second procedure on that arm after a second-round exit at the French Open.

Keys reached the U.S. Open's fourth round each of the past two years. Her best Grand Slam showing was a semifinal appearance at the 2015 Australian Open.

Mertens fell to 0-2 at the U.S. Open. Her best major was this year's French Open, where she lost to Venus Williams in the third round.

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6:57 p.m.

Rafael Nadal says it's too loud in Arthur Ashe Stadium with the retractable roof closed.

The top-seeded Spaniard complained following a straight-sets, first-round victory over Dusan Lajovic on Tuesday that it was so loud he was unable to hear his opponent hitting the ball. Said Nadal: "All the noise stays inside and this is difficult."

That was similar to what other players and fans said last year during the inaugural year of the $150 million sliding cover, describing the collected murmurs of the crowd of 20,000 that combined to form a low-grade noise similar to a buzzing hive or a rushing waterfall.

The U.S. Tennis Association Executive Director Gordon Smith said last year that the organization would look into the level of ambient noise in the stadium.

Nadal's was one of only seven matches completed during the day session Tuesday due to a steady rainstorm.

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5:42 p.m.

Jelena Ostapenko needed three sets and two courts to advance to the second round of the U.S. Open.

The French Open champion finished off a 6-2, 1-6, 6-1 victory over Spain's Lara Arruabarrena in Arthur Ashe Stadium after it was moved from Court 17 because of rain.

The No. 12 seed from Latvia was up 3-1 in the third set when play was suspended, then quickly finished off the victory when they resumed under the roof.

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5:27 p.m.

Jelena Ostapenko and Lara Arruabarrena are getting upgraded to Arthur Ashe Stadium.

Their women's match that began on Court 17 was moved into the main stadium so it could be completed Tuesday afternoon. All other matches that were in progress or still to be played were called off because of rain.

The 12th-seeded Ostapenko led 6-2, 1-6, 3-1 when play had been suspended a few hours earlier. The Latvian won the French Open in June.

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5:10 p.m.

Rafael Nadal has improved to 13-0 in U.S. Open first-round matches by beating Serbia's Dusan Lajovic 7-6 (6), 6-2, 6-2.

The No. 1 seed dominated after a first set that lasted more than an hour. With rain wiping out most of the day's play, Nadal became the first man to complete a match Tuesday.

With his victory, the two-time U.S. Open champion assured that Roger Federer has to reach the semifinals for a chance to regain the No. 1 ranking.

Federer was to play later Tuesday against American Frances Tiafoe.

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3:45 p.m.

Because of rain much of the day, most U.S. Open matches are being postponed.

With one possible exception — French Open champion Jelena Ostapenko against Lara Arruabarrena — all matches that were suspended in progress earlier or have yet to begin on all courts other than Arthur Ashe Stadium will be pushed back to Wednesday.

The Ostapenko-Arruabarrena match, which Ostapenko leads 3-1 in the third set, could get moved from Court 17 to Ashe, where the retractable roof is closed, allowing for play to continue.

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2:19 p.m.

Angelique Kerber is gone from the U.S. Open, the first defending champion eliminated in the first round in 12 years.

The sixth-seeded German is out of the tournament and on her way out of the top 10 after being beaten by Naomi Osaka of Japan 6-3, 6-1 in one of the only completed matches on a rainy Tuesday.

Kerber and Osaka had the stage to themselves after play was suspended on all courts other than Arthur Ashe Stadium, which has a retractable roof that was closed midway through No. 1 Karolina Pliskova's 6-2, 6-1 victory over Magda Linette of Poland.

Kerber then took the same court where she beat Pliskova for the title last year and took another stinging defeat in what's been a season-long slump since winning her second Grand Slam title.

The left-hander fell to 25-18 with no titles in 2017 after she was No. 1 last year.

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1:50 p.m.

The defending women's champion is down a set in the only match going on at the U.S. Open.

Naomi Osaka took the first set 6-3 from sixth-seeded Angelique Kerber under the roof at Arthur Ashe Stadium. Play is suspended at least until 3 p.m. on all other courts because of rain.

Kerber has had a disappointing year after winning here last year for her second Grand Slam title. The German is just 25-17 with no titles in 2017 and has fallen to No. 6. She will need to reach at least the round of 16 to remain in the top 10.

The last defending women's champion to lose in the first round was Svetlana Kuznetsova in 2005.

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12:51 p.m.

Play has been suspended by rain at the U.S. Open on all courts except Arthur Ashe Stadium.

Players have returned to the locker room. A light rain began falling earlier but play was able to continue for a time as workers wiped the courts dry along the lines when necessary.

Ashe has a retractable roof, so No. 1 Karolina Pliskova was able to finish her first-round victory after it was closed between sets. Play was to continue on Ashe as scheduled, with defending champion Angelique Kerber set to begin her match against Naomi Osaka of Japan at 1 p.m.

Rain is in the forecast for Tuesday afternoon.

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12:38 p.m.

No. 1 seed Karolina Pliskova has won her first-round match at the U.S. Open.

Pliskova beat Magda Linette of Poland 6-2, 6-1, slowed only when the players had to break so the retractable roof at Arthur Ashe Stadium could be closed.

The roof closed between sets with light rain falling. Pliskova then quickly finished off the match once play resumed.

Fellow Czech Barbora Strycova also advanced quickly to the second round. The No. 23 seed beat Misaki Doi of Japan 6-1, 6-3.

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12:08 p.m.

The roof has been closed at Arthur Ashe Stadium as light rain falls at the U.S. Open.

Top-seeded Karolina Pliskova won the first set 6-2 against Magda Linette of Poland, then the players waited between sets while the retractable roof was closed.

Last year was the first with the roof covering the main stadium at the Billie Jean King National Tennis Center. Next year, a new Louis Armstrong Stadium will also have a retractable roof.

Staffers wiped the outer courts while fans began raising umbrellas, with hopes that matches would be able to resume quickly.

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11:42 a.m.

Elina Svitolina is into the second set before many fans have even entered the grounds.

The fourth-seeded Ukrainian won the first set 6-0 against Katerina Siniakova from the Czech Republic in less than a half-hour.

Svitolina has a WTA Tour-leading five titles in 2017 and her 45 match victories rank second to Caroline Wozniacki.

Svitolina then won the first game of the second set before Siniakova finally got on the board.

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11:03 a.m.

Roger Federer and Rafael Nadal will play their opening-round matches, while women's No. 1 seed Karolina Pliskova is also in action on the second day of the U.S. Open.

Nadal, who has returned to No. 1, faces Serbia's Dusan Lajovic in an afternoon match in Arthur Ashe Stadium. Federer, seeded third, meets young American Frances Tiafoe on Tuesday night under the lights.

Federer, a five-time U.S. Open champion, is 16-0 in first-round matches at the U.S. Open. Nadal is also unbeaten, going 12-0 while winning the title twice.

Pliskova is scheduled for the first match on Ashe when the Czech faces Magda Linette of Poland.

Defending women's champion Angelique Kerber of Germany and 2009 men's champion Juan Martin del Potro are also on the schedule, with rain in the forecast for later in the day.

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