Australia’s Casey Dellacqua has won her opening round match at the WTA’s Texas Open.

Dellacqua, who came into the draw as a qualifier, scored a 6-2 6-2 win over Irina-Camelia Begu of Romania.

Top-seed Angelique Kerber pulled out of the tournament with a sore shoulder on Monday but remains hopeful of recovering in time for the start of next week’s US Open.

“Last night was not so good, so that’s why I decided to withdraw and to focus on the US Open,” Kerber said.

She said her shoulder had started bothering her in Montreal two weeks ago, and was worse after her run to the final of the Cincinnati Open, where she fell to China’s Li Na last weekend.

Despite the absence of Kerber, Dallas fans saw a three-set thriller on Monday night as former world No.1 Jelena Jankovic, seeded second, pulled off a 6-7 (7-9) 7-6 (7-4) 6-1 victory over Yaroslava Shvedova of Kazakhstan.

Marina Erakovic of New Zealand emerged from a tense battle with Britain’s Anne Keothavong with a 6-1 5-7 7-6 (11-9) victory.

In other matches, third-seeded Roberta Vinci of Italy breezed past Hsieh Su-wei of Taiwan 6-2 6-2, and sixth-seeded Peng Shuai of China defeated Ayumi Morita of Japan 4-6 6-0 6-3.