Volynets heated up while winning the last seven games, as she lost just one point total in the final three games. The result moves her into a WTA Tour quarterfinal for the first time.

Up next for Volynets is a matchup against hometown favourite Peyton Stearns (21), who won the 2022 NCAA women's singles championship for the University of Texas. Stearns downed Sweden's Mirjam Bjorklund (24) 6-3, 7-5 in second-round action.

Fourth-seeded Sloane Stephens (29) of the United States defeated Great Britain's Heather Watson (30) 6-4, 6-4, and Varvara Gracheva (22) produced a 6-3, 6-7 (5), 6-1 win in an all-Russian matchup against Anna Blinkova (24) in Austin.

Abierto GNP Seguros

Third-seeded Donna Vekic (26) of Croatia needed just 80 minutes to rout the United States' Emma Navarro (21) 6-3, 6-2 in the second round at Monterrey, Mexico.

Vekic put just 48 per cent of her first serves in play, but she prevailed by picking on Navarro's second serve, winning 14 of 18 points. Vekic also saved nine of the 11 break points she faced.

Fifth-seeded Lin Zhu (29) of China registered a 7-6 (4), 2-6, 6-3 win over Canada's Rebecca Marino (32), and Belgium's Ysaline Bonaventure (28) topped Russia's Kamilla Rakhimova (21) 7-6 (2), 1-6, 6-3.

In the last match of the night, the United States' Caroline Dolehide (24) eliminated Slovakia's Anna Karolina Schmiedlova (28) 6-2, 6-4.