Flushing Meadows is very close to an area of Queens known as Little Manila because of the large Filipino community, and they flocked to Grandstand Court on Sunday to cheer on 20-year-old Eala, one of the rising stars of the women's tour.
The noise levels rose in a dramatic encounter against Danish 14th seed Clara Tauson, which went all the way to a deciding tiebreak after Eala clawed her way back from 1-5 down in the third set.
The left-hander saw four match points come and go before eventually taking the tiebreak for a 6-3 2-6 7-6 (13-11) victory that was celebrated in raucous fashion.
It made Eala the first woman from the Philippines to win a grand slam singles match in the open era.
"It's so special,'' Eala said. "To be Filipino is something I take so much pride in.
"I don't have a home tournament, so to be able to have this community here at the US Open, I'm so grateful they made me feel like I'm home."
Also making history for Asia was Indonesia's Janice Tjen, who upset 24th seed Veronika Kudermetova 6-4 4-6 6-4, becoming the first player from her country to win a main-draw slam match for 22 years.
World No.1 Sabalenka did not have things all her own way against Rebeka Masarova, but avoided any real danger, claiming a 7-5 6-1 victory.
Sabalenka recovered from an early break down and then showed her defensive skills on a memorable set point to forge ahead, after which she pulled away to victory.
The three-time major winner overcame a shaky start and struggled to find her range, grinding through a tense opening set before racing through the second, feeding off a vocal Arthur Ashe crowd.
"When I won that first set and you cheered me out I got goosebumps," Sabalenka said in her on-court interview.
"Your support means a lot to me, thank you for coming. It was an amazing atmosphere."
The top seed will next face Russian Polina Kudermetova, who became the first winner of this year's tournament when opponent Nuria Parrizas Diaz retired after only four games.
In another first-round clash, British No.1 and 2021 US Open winner Emma Raducanu needed just 62 minutes to sweep aside Japanese qualifier Ena Shibahara 6-1 6-2.
with Agencies
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