Victoria Azarenka withdrew from the Dubai Tennis Championships on Tuesday because of a right foot injury.
Azarenka, coming off a title this past weekend at the Qatar Open, was the top seed in Dubai. She hurt her foot while winning last week's tournament.
"It happened last week," Azarenka said in a statement released through the 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 Qatar final, Azarenka was supplanted by Williams as the top-ranked player in women's tennis on Monday.
Williams is seeded second this week and, because of Azarenka's withdrawal, will retain the No. 1 ranking for at least another week.
Azarenka's place in the draw will be filled by lucky loser Carla Suarez Navarro.