The 43-year-old Williams, handed a wild card entry to the tournament, was beaten 6-1 6-1 by Minnen at Arthur Ashe Stadium. It marked the veteran American’s heaviest defeat at the US Open since she made her debut in 1997, according to Reuters.
“My preparation was definitely minimal,” Williams told reporters after her landmark 100th US Open match. “But I don’t think that it necessarily affected the bulk of my performance.
“I think there are just shots where my footwork wasn’t really there. A lot of backhands I missed where my feet just weren’t there. That’s normal when you don’t spend a lot of time on the court.”
Prior to the tournament, the seven-time grand slam champion had played just nine tour-level matches this year, chalking up three wins in that time.
Against Minnen, she quickly fell to a 0-4 deficit in the first set before getting on the scoreboard with a hold of serve.
However, the 26-year-old varied her shots well as she attempted to move Williams around the court. After wrapping up the first set, she raced into a 5-0 lead in the second and soon completed the victory as Williams drilled a forehand into the net.
“I really have to give credit to her,” the former world No. 1 said of her opponent’s performance.
“It was just incredible, honestly. I mean, if she can play like that, you imagine that she can be in the top 10 or perhaps No. 1 or maybe win a grand slam – something like that – if she can play at this level.”
Minnen next plays another American, world No. 204 Sachia Vickery, as she bids to reach the third round of a grand slam for only the second time in her career.