SAN DIEGO — Katie Volynets rallied to defeat 17-year-old qualifier Clerive Ngounoue 2-6, 6-4, 6-2 in the first round of the Cymbiotika San Diego Open on Monday night at the Barnes Tennis Center.

Ngounoue had won two qualifying matches during the weekend and was hoping to win her first WTA main draw match.

Volynets, 21, of Walnut Creek, California, won the USTA Billie Jean King Girls’ 18s National Championship in 2019, the same event Ngounoue won last month, also at the Barnes Tennis Center.

“I thought coming in here that I would have the edge, having won it when I was 17,” said Volynets. “I know she plays well here, so I’m happy I was able to get through.”

Ngounoue, a hard-hitting right-hander from Washington, was competing in her first WTA 500 main draw after launching her pro career.

“I was expecting a fight and I knew she’s a fighter,” Ngounoue said. “She played really well, but I think I learned a lot of things to take from it.”

Earlier Monday, following a 2-hour, 15-minute rain delay that halted play at 3-3 in the third set, Russia’s Anastasia Potapova recorded a 6-2, 5-7, 6-4 win over Alycia Parks of the United States.

“It was a very tough from the first point,” Potapova said. “The actual temperature didn’t seem so hot, but it felt very hot, especially for a long match. I’ve played in a lot worst weather, so I enjoyed it.”

Top-seeded Ons Jabeur of Tunisia, the event’s highest-ranked player at No. 7, received a first-round bye and will play her first match on Wednesday.

First-round matches continue on Tuesday as last year’s semifinalist Danielle Collins is scheduled to face fellow American Louisa Chirico, a qualifier from Harrison, New York.

Wild-card entrant Leyla Fernandez of Canada, a finalist at the 2021 U.S. Open, will meet seventh-seeded Beatrice Haddad Maia of Brazil.

Former U.S. Open champion Sloane Stephens will take on Elise Mertens of Belgium, who fell in the second round of this year’s U.S. Open, losing in three sets to eventual winner Coco Gauff.