French Open runner-up Sara Errani and former Wimbledon champion Petra Kvitova notched first-round wins, while last week's Doha titlist and top-seeded Victoria Azarenka pulled out of the $2 million Dubai Tennis Championships on Tuesday.
The 2010 Dubai runner-up Azarenka withdrew because of a right foot injury, which she said bothered her during last week's title run in Qatar.
"It happened last week," Azarenka said in a statement released through the Dubai tournament. "I have been obviously playing on it a lot, so going to a new tournament is too much to handle right now. It keeps getting worse. It was an unfortunate decision that I had to make, and obviously I'm very disappointed with that."
Despite a 14-0 match record to start the season, a second straight Australian Open championship and a victory over Serena Williams in the Doha final, Azarenka was supplanted by the Wimbledon and U.S. Open champion Williams as the top-ranked player in women's tennis this week.
Azarenka's place in the draw will be filled by lucky loser Carla Suarez Navarro.
On the court in Dubai on Tuesday, a fifth-seeded Errani got past German Julia Goerges 6-3, 4-6, 6-4 and a sixth-seeded Kvitova whipped Slovakian qualifier Daniela Hantuchova 6-2, 6-1 at Dubai Tennis Stadium. Goerges was last year's Dubai runner-up to Wimbledon finalist Agnieszka Radwanska.
In other matches involving seeds, No. 7 former U.S. Open champion Samantha Stosur clobbered Russian Ekaterina Makarova 6-3, 6-1 and No. 8 Caroline Wozniacki pasted Czech Lucie Safarova 6-2, 6-2. The former world No. 1 Wozniacki was the Dubai champion two years ago.
Also on Day 2, Chinese Zheng Jie snuck past Pole and fellow qualifier Urszula Radwanska 6-2, 2-6, 7-5, Russian Nadia Petrova overcame Slovak Dominika Cibulkova 5-7, 6-3, 6-2 and Italian Roberta Vinci drubbed qualifier and former top-five star Svetlana Kuznetsova 6-3, 6-2. The two-time major champion Kuznetsova was the Dubai runner-up in 2004, 2008 and 2011.
In some second-round action on Wednesday, a second-seeded Williams will battle former Wimbledon runner-up Marion Bartoli and the third-seeded and defending Dubai champion Radwanska will face Kazakhstani wild card Yulia Putintseva.
Errani, Kvitova, Stosur and Wozniacki will also take to the courts on Day 3, highlighted by a match between Kvitova and former top-ranked star Ana Ivanovic.
The 2013 Dubai champion will earn $442,198.