Serena to rest for a week due to elbow injury

Williams, who will bid to complete a rare calendar grand slam at Flushing Meadows, withdrew ahead of her second-round match against Klara Koukalova after sustaining the injury during practice.

(Reuters)

"As much fun as we have been having the past 8 or so weeks I have to take some time to let my elbow heal," Williams said in a post on her Facebook page.

"I am confident it will be ready for the rest of the summer. I need some time to recover and rehab it, but as of now I am being forced to take the next week off."

The 33-year-old, who won her sixth Wimbledon singles tennis title this month, is scheduled to defend her title at Stanford from Aug. 3 and play the Rogers Cup in Toronto the following week ahead of the U.S. Open, which starts on Aug. 31.

(Reporting by Ian Ransom in Melbourne; Editing by Peter Rutherford)