NEW YORK (AP) -- Sloane Stephens came back to a whole new U.S. Open.
From a rebuilt stadium to a revamped schedule, Flushing Meadows had quite a different look.
More second looks, too: For the first time in any Grand Slam tournament, there was electric line calling on all courts.
Throw in new serve clocks and the changes provided some new challenges for Stephens on Monday as she opened her title defense with a 6-1, 7-5 victory over Evgenia Rodina.
That match was played in the new Louis Armstrong Stadium, with obstacles she didn't face last year when her final few matches were in Arthur Ashe Stadium.
"It was fun to play first day on a brand-new stadium court," Stephens said. "But there was a lot happening."
Like the noticeable movement of fans to and from the concession stands along the concourse of the 14,000-seat stadium with a retractable roof. Patrons can see the action from the concourse, and they gathered in large numbers until they were allowed back to their seats during changeovers.
Except for the times when they didn't wait at all.
Not that it was just the foot traffic. For Stephens, it felt like planes, trains and automobiles.
"There was a lot going on, like I said, between the airplanes and the subway behind the court, the concessions being in the lower bowl, and people walking in the games at, like, 2-all, 3-all," she said. "There's just a lot going on."
The serve clocks are being used for the first time in a Grand Slam as a way to speed up the pace of play. The clocks are mounted on the walls toward the corners, not particularly noticeable for fans or even for fast-playing players. American Sam Querrey said he rarely even looks at the clocks because he's used to serving well within the 25-second limit.
But it was yet another obstacle for Stephens, along with the new types of noise.
"Between that and the shot clock, I got so much going on on the court," she said. "I'm trying to manage, like, eight different things. Oh, God, just relax a bit."
There were some benefits to Armstrong, though. Andy Murray noticed them while winning the second official match on the new court after top-ranked Simona Halep was upset in the opener.
"I think it's a bit easier to play on than the old Armstrong," he said. "It's a little bit more sheltered from the wind, although, you know, you can get a breeze in there. It's kind of, before it used to swirl a lot in the old Armstrong. Now it's sort of, it blows but tends to go in one direction.
"Also, it's shaded from quite early on in the day, which is nice for the players and also, I think, the people watching, as well, for the fans."
Following the victories by Murray and Stephens, there was a separate Armstrong night session for the first time, featuring two matches.
Victoria Azarenka won the opener of that session in her return to the U.S. Open, where she hadn't played since giving birth to her son in 2016. She said she hated playing on the old Armstrong, so she was delighted to try something new in at a tournament where everything from the logo to the chair umpires' furniture has changed following a five-year, $600 million project that remade the USTA Billie Jean King National Tennis Center.
"Not necessarily a new place," she said, "but definitely an upgraded one."