NEW YORK -- A drone buzzed over the court during a US Open match in Louis Armstrong Stadium on Thursday night and crashed into an empty section of seats.
U.S. Tennis Association spokesman Chris Widmaier said no one was injured and that the New York Police Department was "conducting an ongoing investigation."
Pennetta said she heard the drone fly by and was not sure what it was.
Her initial reaction, she said afterward, was that it might have been a bomb.
"A little bit scary, I have to say," Pennetta said.
"With everything going on in the world ... I thought, 'OK, it's over.' That's how things happen," she said.
She said neither the chair umpire nor tournament officials told her that it was, indeed, a drone.
It broke into pieces upon landing, and the match was only briefly interrupted between points while police and fire department personnel went to look at it.
"The chair umpire just wanted to wait for an OK from the police to be able to continue, even if, truthfully, I don't think even they knew what it was," Pennetta said.
Pennetta said her coach and physical therapist were sitting in the opposite end of the stadium from where the drone crashed and that they told her later they were afraid, too.
"All of these [security measures], and then it comes in from above," Pennetta said.
The episode happened a little before 8:30 p.m., during the day's last match in Louis Armstrong Stadium, which has a seating capacity of about 10,000. Pennetta and Niculescu originally were scheduled to play on much smaller Court 17, but their match was moved because four earlier matches in Armstrong wrapped up early.
"If there had been spectators, it would have hit them and done a lot of damage," Pennetta said.