Injured Azarenka out of Dubai

Top seed Victoria Azarenka has pulled out of this week's Dubai Duty Free Tennis Championships with a foot injury.

The Australian Open champion lost her world number one ranking to Serena Williams on Monday, despite beating her in the final of the Qatar Open on Sunday, and is now likely to drop further behind the American.

Azarenka said of the injury: "It happened last week. 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."

Azarenka is yet to lose a match this year, although she did withdraw from her opening tournament of the season in Brisbane ahead of a scheduled semi-final against Williams because of a toe problem.