Venus Williams celebrated her 20th anniversary at the US Open on Monday as the tournament celebrated 20 years of Arthur Ashe Stadium, where she claimed two of her seven Grand Slam titles.

Williams was a 17-year-old upstart with beads in her hair when she rallied to defeat Latvia's Larisa Neiland 5-7, 6-0, 6-1 in the first round of the 1997 US Open in her Flushing Meadows debut on her way to her first Grand Slam final, which she lost to Martina Hingis.

"It has been 20 wonderful years," Williams told the crowd after a 6-3, 3-6, 6-2 first-round victory over Slovakian qualifier Viktoria Kuzmova.

"I'm not sure there are going to be 20 more."

Since Williams became the first unseeded US Open women's finalist since 1958, she has won the 2000 and 2001 US Opens and five Wimbledon crowns, including her most recent Slam title in 2008.

But this season, at age 37, Williams has turned back the clock, reaching the finals at Wimbledon and the Australia Open.

She lost to Spain's Garbine Muguruza on the All England grass and to her pregnant sister Serena at Melbourne last January.

She reached Arthur Ashe Stadium having played in two Grand Slam finals in a year for the first time since 2003, marveling at the largest venue in tennis from her airplane window.

"It's massive. When I was flying in, we flew right over it," Williams said. 

"A certain excitement I get to play there. It's a privilege. It's an honor. I take it quite seriously. Everybody does."

Asked what her career timetable might be, the oldest woman in the US Open said, "I don't know. We'll see. I have no plans. Zero."

Well, she has one. With 23-time Grand Slam winner Serena giving birth in the next few weeks, Venus will become an aunt for the first time as an adult. It's one of the few adventures the sisters haven't been able to fully share in their careers.

"It's definitely a different experience, especially for she and I, because we spent our whole lives so focused on work," Venus said. "So when you have an experience that is not work, it's pretty intense. It's a completely different experience for both of us."

- 'It won't be forever' -

Tour life without Serena has Venus spending more time down Memory Lane than just a landmark night at Arthur Ashe Stadium.

"I definitely have adjusted at this point. It takes time," Venus said. "There are moments where you have very distinct memories of togetherness.

"I've been able to remember those and be fond or have some longing or happy memories, all those feelings. But the plan is hopefully that it won't be forever."

Until Serena is able to return as doubles partner and singles star, something she has said her goal would be to do in time to defend her Australian Open title in 2018, Venus will have to settle for some coaching advice from afar.

"We always coach each other pretty much. We know what it's like to be out there," Venus said. "It's like I know I relate to her, she relates to me. I know exactly what it feels like. It's great to get advice from someone like that."

Especially when your game is making a return to star form like that of Venus.

"I feel like my game always rises a lot in the bigger events," she said. "That's what I feel like, like I'll be ready to play when push comes to shove."