Slovakian Daniela Hantuchova maintained her resurgence with a surprise victory over sixth seed Victoria Azarenka at the Qatar Open on Tuesday.
The former top-tenner recovered from dropping a 68-minute opening set at the Khalifa Tennis Centre to win 4-6 6-1 6-2.
Hantuchova, who recently claimed her first WTA title for three years in Pattaya, reeled off the final six games to book a second-round match against Russian Vera Dushevina.
Israel's Shahar Peer made light of the worst draw for any seeded player with an impressive 6-2 6-4 defeat of in-form Svetlana Kuznetsova, the world number 13.
Eighth seed Peer's task was made slightly easier as Kuznetsova, beaten by world number one Caroline Wozniacki in the Dubai final last week, was hampered by a foot injury.
Wozniacki faces Russia's Nadia Petrova in second-round action on Wednesday.
Fifth seed Jelena Jankovic was given few problems in her first round against Omani wildcard Fatma Al Nabhani, winning 6-1 6-3 against the 19-year-old and India's Sania Mirza beat Serbia's Bojana Jovanovski 6-2 7-5.