The United States' Ashlyn Krueger rallied in front of a supportive crowd on Tuesday, pulling off a 5-7, 7-6 (4), 6-2 upset of No. 16 seed Donna Vekic of Croatia in the first round of the Cincinnati Open at Mason, Ohio.

Krueger and Vekic each had nine aces, with the former overcoming 14 double faults to punch her ticket to the second round.

It was a surreal victory for Krueger, who attended the Cincinnati Open when she was a kid.

"I came here with my family when I was 12, it's the only pro tournament I've ever been to -- twice," an emotional Krueger said. "So to play here on this court, I remember watching from the stands."

Vekic was unable to ride any momentum she garnered from winning the silver medal in women's singles at the Paris Olympics.

Russian Daria Kasatkina, the No. 9 seed, and Ukrainian Marta Kostyuk, the No. 15 seed, managed to ward off upsets. Kasatkina swept countrywoman Ekaterina Alexandrova 6-4, 6-2, while Kostyuk outlasted Elise Mertens of Belgium for a 6-4, 2-6, 6-4 win.

Kasatkina saved 5 of 6 break points in knocking off Alexandrova.

Robin Montgomery failed to join fellow American Krueger in the second round, as Italy's Elisabetta Cocciaretto prevailed 7-5, 4-6, 6-3 in their match. Montgomery had nine aces but was hampered by 12 double faults.

Other winners Tuesday included New Zealand's Lulu Sun, Varvara Gracheva of France and Czech Karolina Pliskova.

Things are bound to get a lot tougher for Gracheva in the second round, as she is set to face top seed and world No. 1 Iga Swiatek of Poland. Swiatek was bounced in the semifinals of last year's Cincinnati Open, falling to eventual champion Coco Gauff of the United States.

Meanwhile, Pole Magda Linette, Ukrainian Elina Svitolina and Kazakhstan's Yulia Putintseva all came from behind to oust their respective opponents.

Linette came away with a 2-6, 6-0, 7-5 win against Great Britain's Katie Boulter, Svitolina got past Yafan Wang of China, 5-7, 6-3, 6-2, and Putintseva knocked off another Brit, defeating Harriet Dart 4-6, 6-0, 6-1.

Putintseva lost her serve to open the third set before taking the next six games.

Russia's Anastasia Potapova also won in three sets, sinking Clara Burel of France 6-4, 2-6, 6-1. Potapova won 32 of 46 first-serve points.

In the final match of the night, Armenian qualifier Elina Avanesyan cruised to a 6-4, 7-5 victory over Canada's Bianca Andreescu.

--Field Level Media