Former Wimbledon champion Petra Kvitova got out of the first round of the Dubai Championships for the first time in three visits by easily handling Daniela Hantuchova 6-2, 6-1.
Kvitova, seeded sixth, broke the Slovak qualifier five times, the last when Hantuchova double-faulted twice in the final game.
Kvitova set up a second-round match with former No 1 Ana Ivanovic.
Another former No 1, Caroline Wozniacki, had little trouble against 18th-ranked Lucie Safarova, beating her 6-2, 6-2.
Wozniacki, the 2011 Dubai champion, was on course to meet new No 1 Serena Williams in the quarterfinals.
Williams, who received a first-round bye, became the highest seed at No 2 when Victoria Azarenka withdrew because of a right foot injury she said she had been carrying for a week, while defending her Doha title and beating Williams in the final at the weekend.
"I tried (to play), but my body says no. I cannot force (it)," Azarenka said. "I cannot put myself in a position to hurt myself. That would just be stupid."
She intended to travel to the United States to prepare for the big Indian Wells event next month.
Meanwhile, Williams had her eye on ending her Dubai title drought on her fourth visit. Her big sister Venus has won the tournament twice, but Serena's three previous visits didn't end so well. On her debut in 2005, she had to retire in the semi-finals. In 2008, she withdrew before the tournament because of the flu, and in 2009 she fell to Venus in the semis.
This time around, Williams said she was healthy - she had a flu bug last week - and upbeat even after losing the final in Doha on Sunday.
"I feel so much better this week," Williams said. "I feel like a completely different athlete, a completely different person."
Having become the oldest No 1 in the WTA's rankings history on Monday, Williams said she was proud to have regained the ranking after a tumultuous few years, and was moving on in search of a 48th career title and more Grand Slam success.
"I feel like I'm at a place where I reached that goal of getting back to the top," she said. "If I stay that would be great and if not then I've done it."
She's set to meet Marion Bartoli in the second round.