MOSCOW (AP) Last year's runner-up Irina-Camelia Begu was among the winners on the first day of main draw play at the Kremlin Cup on Monday, while Angelique Kerber withdrew from the tournament.
Romania's Begu, seeded seventh, was made to work hard in a 6-1, 7-6 (2), 6-2 win over Bulgaria's Tsvetana Pironkova that lasted more than two hours.
Begu, the world No. 29, next faces either Poland's Paula Kania or Daria Kasatkina of Russia in the second round.
Kerber cited a back injury as the reason for her withdrawal. She joins Agnieszka Radwanska, who pulled out Sunday saying she wanted to recover after winning the Tianjin Open.
In the men's competition, seventh-seeded Joao Sousa of Portugal went out in the first round, losing 7-6 (2), 4-6, 7-5 to Spain's Daniel Gimeno-Traver.