She heads to the third round looking every bit ready for a three-peat.
The top-seeded Sabalenka overwhelmed Polina Iatcenko 6-1 6-1 in 53 minutes on Wednesday night, putting on a power-hitting display that made it seem her recent problems are in the past.
Sabalenka won 15 of 16 points on first serve in the first set and only dropped off a little in the second, finishing 21 for 28 in the match.
Sabalenka is trying to become the first player to win three in a row in Flushing Meadows since Serena Williams from 2012-14, but arrived after losing in the fourth round of her past three tournaments. She needs help to stay atop the WTA rankings even if she wins the title.
But she made it clear if she loses the top spot, it won't be without a fight.
"Happy with the level I played today, happy with the focus and happy to be through this match," she said.
Fellow seeded players Jessica Pegula and Karolina Muchova also dispatched of their opposition in lightning-quick time.
No.3 seed Pegula needed only 56 minutes to defeat Sofia Kenin 6-3 6-1, after the 2020 Australian Open champion beat Venus Williams in her first match.
"To be out of there in under an hour, it doesn't always happen," Pegula said. "So I think I'm just going to take that one and run, I guess, until the next round."
World No.7 Karolina Muchova stormed into the third round with a crushing 6-1 6-0 victory over Britain's Katie Boulter.
Rain forced the meeting to be moved to the roofed Louis Armstrong Stadium and the two-time semi-finalist at Flushing Meadows was ruthless from start to finish.
World No.62 Boulter, who recently married Australian tennis ace Alex de Minaur, briefly threatened to make a contest of it by breaking Muchova's first service game, but she struggled to find any rhythm after that.
Muchova recovered immediately and took full advantage of Boulter's unforced errors, 15 of which came in the first set alone, to take the opener.
The second followed much the same script, with the Czech continuing to dictate play while Boulter failed to hold serve throughout the match, allowing Muchova to secure the win in under an hour.
With rain coming down for a second day in New York, play was suspended again for a time on outside courts, allowing only play under the roofs in Arthur Ashe Stadium and Louis Armstrong Stadium to continue uninterrupted.
Those are second-round matches, while some players were still playing their first. When the US Open switched to a Sunday start last year, it spread out the first round over the first three days, so Wednesday would have arrived with everyone playing in the second round had the weather cooperated.
It hadn't, and some players were not only still playing their first match, but they had to hope the weather cleared enough later so they wouldn't have to resume it Thursday.
No.11 seed Marta Kostyuk also advanced, getting past 2017 US Open champion Sloane Stephens 6-1 7-5, while Emma Navarro beat Caty McNally 3-6 6-2 6-3.
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