Keothavong lost the first set but hit back strongly
British number two Anne Keothavong reached the second round of the ASB Classic in Auckland with a hard-fought win over Edina Gallovits of Romania.
Keothavong lost the first set but hit back for a 6-7 (4-7) 6-4 6-0 win.
Britain's Heather Watson beat Italy's Alberta Brianti 6-3 6-2 in qualifying - but Brianti entered the main draw after Anastasija Sevastova fell ill late on.
However, she was put in to face Russian top seed Maria Sharapova - who cruised to a 6-2 6-3 victory.
Sharapova was relieved to begin 2011 with a win and played down the significance of her match being delayed by two hours because of the change of opponent.
"I've been on the tour for many years and, by now, I'm really used to it," she said.
"I've often played after the guys at tournaments and been warming up at two sets to none, only to wait around for another three hours.
"That's the way it goes and you just have to be ready."
Next up, Sharapova meets Czech Renata Voracova, who beat Lourdes Dominguez Lino 4-6 7-6 (10/8) 6-0.
Another Russian Svetlana Kuznetsova, seeded third in Auckland, progressed with a 6-4 6-2 win over home hope Sacha Jones.
Forty-year-old Kimiko Date-Krumm lost 6-4 6-3 to Kateryna Bondarenko and Shuai Peng thrashed Johanna Larsson 6-1 6-3.
But Katie O'Brien lost against Thailand's Noppawan Lertcheewakarn in the final round of qualifying on Monday.
Earlier Watson, ranked 176 in the world, had beaten American Jamie Hampton and Italian Corinna Dentoni to reach the final round of qualifying, and she put the pressure on world number 91 Brianti from the start.
The Briton led 4-1 before the 30-year-old Italian broke back, but Watson moved 5-3 clear and then won four straight points from 15-40 down to take the first set in 39 minutes.
Watson powered into a 2-0 lead at the start of the second and made it four breaks of serve to one in game seven, wrapping up the victory in one hour and 14 minutes.