Venus Williams is 39 years old, and ranked outside the top 50. She hasn’t gotten past the third round of a major in two years. But Monday she sure looked ready to turn back the clock.

Williams eviscerated Saisai Zheng 6-1, 6-0 in a first-round U.S. Open rout that was every bit as one-sided as it sounds. Maybe more so.

“I was happy with [the performance], so I’m not going to ask for more. Whether the win is easy or whether it’s tough, a win is a win,” Williams said. “Getting to the next round is about getting the win on your side and building yourself up during the tournament and patting yourself on the back for every good achievement.”

One couldn’t blame Williams for taking a pat on the back and a few bows for good measure. She hasn’t advanced past the third round of a major since 2017, but turned in a master class that belied her 52nd ranking and showed her focus is as sharp as ever.

“It’s a wonderful job, and it’s all-consuming. So if you don’t love it, it’s really hard to do well at it,” Williams said. “The fact that I’ve done well has shown that I’ve loved it and will love it, and I’ll always love it.”

Williams hit 25 winners to her foe’s half dozen. She hit 121 mph on her serve and was pinpoint with it, winning 81 percent on her first serve.

She was aggressive, moved well and did damage coming to net. She opened the second set coming up to dig out her foe’s low backhand, and sealed the point by elevating for a forehand volley. She moved to 22-0 in first-round matches at the U.S. Open, and few were better than this.

“I don’t recall the first rounds that much anymore, but this was a good one,” Williams said. “She’s playing really well, honestly, confident, does everything well. So it was great to be able to perform well against her. Good win.”

Next up for Williams is No. 5 Elina Svitolina, who beat American teen Whitney Osuigwe. The Ukrainian won this year’s French Open meeting 6-3, 6-3.

On a day that Althea Gibson — who broke tennis’ color barrier — had a statue dedicated to her outside Arthur Ashe Stadium, Williams spoke about what it took for one of her idols to excel as a black woman in the 1950s.

“So many qualities that you have to [have], with what she dealt with,” Williams said. “You can’t find a doubles player. Who knows what kind of line calls she got. I mean, I don’t think people really — I don’t even get it. I really don’t. I don’t think anyone really understands what it was like in those days.

“My mom and dad do because they grew up in the ’40s, ’50s, in Mississippi and Louisiana. This is a country where we came here for freedom and it was unfortunate that many people were not given that. And because of Althea, people fighting for it, we’ve gotten a lot closer to it.”