NEW YORK (AP) — The Latest on the U.S. Open tennis tournament (all times local):

12:35 p.m.

Simona Halep has become the first No. 1-seeded woman to lose in first round of the U.S. Open in the professional era.

Halep was beaten 6-2, 6-4 by 44th-ranked Kaia Kanepi of Estonia on Monday in a match that was stunningly lopsided and lasted all of 76 minutes.

It was the first match at the rebuilt Louis Armstrong Stadium.

Halep won the French Open in June for her first Grand Slam title.

But this is the second year in a row she exits the U.S. Open in the first round.

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11:45 a.m.

Top-ranked Simona Halep is off to another slow start at a Grand Slam tournament. She can only hope things turn out as well at the U.S. Open as they did at the French Open.

Playing in the first match at the rebuilt Louis Armstrong Stadium, Halep dropped her opening set against No. 44 Kaia Kanepi of Estonia 6-2 in 28 minutes.

At Roland Garros in late May, Halep ceded the opening set of her first-round match by that same score against 83rd-ranked Alison Riske, before coming back to win that match 2-6, 6-1, 6-1 before eventually claiming her first major championship.

Halep lost in the first round at last year's U.S. Open to 2006 champion Maria Sharapova.

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10 a.m.

A long list of returns highlights Day 1 at the U.S. Open as the year's last Grand Slam tennis tournament gets started.

The schedule Monday includes Serena Williams, Andy Murray and Stan Wawrinka — all past champions at Flushing Meadows who missed last year's U.S. Open.

In addition, defending champions Rafael Nadal and Sloane Stephens are slated to play.

Williams will face Magda Linette in Arthur Ashe Stadium to start the night session, followed by Nadal against David Ferrer in a rematch of the 2013 French Open final.

No. 1-ranked Simona Halep takes on Kaia Kanepi in the first match ever played in the reconstructed Louis Armstrong Stadium, which now features a retractable roof.

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