Doha - Former world number one Ana Ivanovic, who has beaten both Williams sisters this year, began her quest for a first ever Qatar Open title with an unexpectedly sudden finish against Daniela Hantuchova in the first round.
Ivanovic only just saved the first set against the Slovakian former world number five with a last moment break back, and a lengthy struggle seemed likely until Hantuchova stopped with a knee problem early in the second set.
The victory took Ivanovic within two wins of a possible quarter-final meeting with another big name - Li Na, the top-seeded Australian Open champion from China.
"It's never easy to finish like this and I hope she (Hantuchova) will get better, but the first set was really competitive and I am happy that I won that set," the ninth-seeded Serbian said.
She had to survive a great deal of early pressure from Hantuchova who took risks in order to dominate and maintained an advantage of a break of serve from the third game onwards until she had the chance to serve for the set at 5-4.
Then Hantuchova's control failed her, as she missed twice with backhand drives and delivered a double fault. That not only allowed her opponent back into it but offered belated encouragement which helped Ivanovic raise her game.
Ivanovic recovered from 40-love in Hantuchova's next service game, and even though the Slovakian saved one set point well with a good first serve setting up a searing backhand winner she then delivered a moderate second serve on the next set point. It enabled Ivanovic to punish it.
The finish arrived shortly afterwards, with Ivanovic progressing to a second round match against Klara Zakalapova, the world number 34 from the Czech republic. If she wins again she may find Angelique Kerber, the sixth seeded German barring her path.
Australian Open finalist Dominika Cibulkova also had to retire early from her match.
The tenth-seeded Slovakian was struck down with a stomach bug not long before her match, and considered quitting the tournament altogether.
Instead she struggled through eight games against Alisa Kleybanova, the former top 20 Russian, and somehow led 5-3 without feeling better, but then called a halt when her opponent pegged back the score to 5-5.
"I was really looking forward to playing this week in Doha," said Cibulkova.
"Unfortunately I became very sick today and suddenly did not feel well. I wanted to give it a try today and I did everything I could to play, but I could not continue."
It offered good fortune which few would begrudge Kleybanova, a wild card entry who is still trying to rebuild her career after two years away from the circuit with Hodgkin's lymphona, a rare form of cancer.
The top eight seeds begin their campaigns on Wednesday, with Li, the favourite, starting against Magdalena Rybarikova, the world number 32 from Slovakia.
The plum second round match however appears to be that between Venus Williams, the seven times Grand Slam winner from the United States and Petra Kvitova, the former Wimbledon champion from the Czech republic.
Results from the second day of the WTA Qatar Open in Doha on Tuesday (x denotes seeding):
Bettanie Mattek-Sands (USA) bt Eugenie Bouchard (CAN x15) 7-5, 6-1
Samantha Stosur (AUS x12) bt Marina Erakovic (NZL) bt 6-4, 6-2
Lucie Safarova (CZE) bt Kirsten Flipkens (BELx16) 5-7, 6-4, 6-4
Ana Ivanovic (SRB x9) bt Daniela Hantuchova (SVK) 7-5, 2-0 retired
Yanina Wickmayer (BEL) bt Andrea Petkovic (GER) 6-4, 6-4
Magdalena Rybarikova (SVK) bt Francesca Schiavone (ITA) 7-5, 4-6, 7-6 (7/3)
Shuai Zhang (CHN) bt Maryna Zanevska (UKR) 6-3, 6-2
Klara Zakopalova (CZE) bt Elina Svitolina (UKR) 6-2, 6-4
Karolna Plskova (CZE) bt Cagla Buyukakcay (TUR) 6-3, 6-3
Stefanie Vgele (SUI) bt Alize Cornet (FRA) 7-6 (8/6), 7-5
Karin Knapp (ITA) bt Caroline Garcia (FRA) 6-4, 6-1
Kaia Kanepi (EST) bt Varvara Lepchenko (USA) 6-3, 6-4
Monica Niculescu (ROM) bt Fatma Al Nabhani (OMA) 6-1, 6-0
Jana Cepelov (SVK) bt Kristina Mladenovic (FRA) 6-4, 7-6 (7/5)
Anastasia Pavlyuchenkova (RUS) bt Tadeja Majeric (SLO) 5-7, 6-2, 6-3
Mirjana Lucic (CRO) bt Yvonne Meusburger (AUT) 4-6, 6-2, 6-3
Sorana Cirstea (ROM) bt Alla Kudryavtseva (RUS) 2-6, 6-1, 7-5