Luke Lendler, 9, likes Madison Keys. "But I really want to see Serena Williams make history," said the boy who drove up from Philadelphia Sunday with his parents.

He and thousands of other fans, including from Long Island, came out to the U.S. Open in Flushing Meadows, where Serena Williams took center court and moved one step closer to entering the record books with a win over Keys.

Williams beat Keys in straight sets, 6-3, 6-3. Now she'll face her sister, Venus Williams, in the quarterfinals.

Before the match, as an international crowd streamed from the No. 7 subway and Long Island Rail Road platform, staff on bullhorns blared instructions. No backpacks. No aerosol. No selfie sticks.

"They're a hazard," explained the man on the microphone, from Lindenhurst, who said he couldn't give his name.

As the match got under way, fans stopped to watch the big screen on the front of Arthur Ashe Stadium.

Amy Madmon, of the Five Towns area, had taken her 9-year-old nephew Matthew, to watch. She was rooting for a good match. Matthew was a Serena fan. "It's a player he recognizes," she said.

Jonathan Lippin, 62, of Port Washington, took his son Brian, 13, to the U.S. Open for the fifth time.

"It's a happening," Lippin said. "It's the World's Fair of tennis."

Lisa Helfer, 41, of Manhattan, comes every year, reminding her of tournaments her dad would take her to as a child. "I just like the whole atmosphere," she said after taking a selfie -- without a stick -- with her friend in front of Arthur Ashe Stadium fountains.

"It's Serena," said Vickie Peaire, 53, from Denver, North Carolina, of the day's biggest draw. "I'm so excited I can't stand it!"

She, though, cheered for Keys, a 20-year-old American. "I always root for the young up-and-coming underdog."

Williams is going for a Grand Slam -- winning every major event in a year -- and her fifth major in a row.

For the first time, the women's final this year sold out before the men's. Through its first five days, 301,058 fans came through the gates and there were sellouts to all-night sessions, according to the U.S. Open. It is the first time since 2009 that attendance at the U.S. Open exceeded 300,000 through the tournament's first five days.