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Williams needed 1 hour and 37 minutes to defeat her 23-year-old compatriot.

Seven-time Grand Slam singles champion Williams is the oldest player to win a tour-level singles match since then-47 year-old Martina Navratilova beat Catalina Castano at 2004 Wimbledon - more than 21 years ago.

"You know, it's the first step, and the first match is always extremely difficult," Williams said. "It's hard to describe how difficult it is to play a first match after so much time off.

"So going into the match, I know I have the ability to win, but it's all about actually winning. So this is the best result, to play a good match and win. I'm here with my friends, family, people I love, and the fans, too, who I love and they love me, so this has been just a beautiful night."

Williams was already the oldest player to contest a tour-level singles match since then-46 year-old Kimiko Date lost her first-round match at 2017 Tokyo. Williams will now get to contest at least one more.

This was Williams's first singles win since she beat then-World No. 16 Veronika Kudermetova at 2023 Cincinnati - meaning her last two wins have come over Top 35 players, almost two years apart.

"There are no limits for excellence," Williams said. "It's all about what's in your head and how much you're able to put into it. If you put in the work mentally, physically, and emotionally, then you can have the result. 

"It doesn't matter how many times you fall down. Doesn't matter how many times you get sick or get hurt or whatever it is. If you continue to believe and put in the work, there is an opportunity, there is space for you."

Williams will face another Top 35 player in the second round: she will have her first career meeting with World No. 24 Magdalena Frech of Poland. No. 5 seed Frech beat qualifier Yuliia Starodubtseva 6-2, 6-4 in the first round on Monday.

Williams dropped serve at love in the first game of the match, but that, in fact, did not set the tone. Williams cranked her returns up to high volume and immediately got the break back, then continued to press Stearns into errors as the veteran collected the opening set.

In the second set, Stearns went on a 10-point run that saw her take a 3-1 lead, culminating with a love break after a rally backhand winner. But once again, Williams struck right back with power plays of her own, quickly reeling off the next four games to lead 5-3.

A marathon game followed, where Williams had four match points but could not convert. Stearns held on for 5-4 and the meeting continued to the Williams delivery, where Williams saw a fifth match point slip away and faced a break point.

But Williams evaded that peril and earned a sixth match point after a netted return by Stearns. There, a booming serve by Williams closed out the landmark victory. Williams won 71 percent of her first-serve points, as well as 70 percent of points returning second serves.

"I think there were times where I was just trigger-happy," Williams said. "Going crazy really fast, and I sort of convinced myself to play those points, be patient, slow down.

"I think it was a big win for me today. Like I said, it's not easy. It won't be easy. It's not easy for anyone out here. So I know I'll have to fight for every match, but I'm up for that."