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 1-6, 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.
''I don't feel 100 percent ready. The doctors recommended I rest so that I can recover,'' Kerber said in comments released through the tournament organizers.
Svetlana Kuznetsova, ranked 32nd in the world, wrapped up a straightforward 6-0, 6-3 win over Czech player Katerina Siniakova. She next faces Czech qualifier Klara Koukalova.
Last year's Australian Open finalist Dominika Cibulkova of Slovakia also reached the second round with 7-5, 6-1 over Russian wild card entry Elena Vesnina. Awaiting Cibulkova next is a tricky meeting with fifth-seeded Carla Suarez Navarro, who is in the hunt for a place at the tour finals.
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.
Sousa had reached the final at the St. Petersburg Open this season, but more success in Russia eluded the Portuguese player as he lost a close match against Gimeno-Traver, who goes on to play either Italy's Simone Bolelli or France's Lucas Pouille.
There was also an easy win for Russian player Teymuraz Gabashvili, the world No. 57, who swept past Turkish wild card Cem Ilkel 6-2, 6-1. That sets up a second-round meeting with third-seeded Serbian Viktor Troicki.
This story has been corrected to show that Irina-Camelia Begu beat Tsvetana Pironkova 1-6, 7-6 (2), 6-2, not 6-1, 7-6 (2), 6-2