Defending champion Andreescu pulls out of US Open

Last year's US Open winner Bianca Andreescu has decided not to defend her title after announcing her withdrawal from the event.

The Canadian has yet to fully recover from the knee injury she suffered at the WTA Tour Finals in October. 

"I have made the difficult decision not to return to New York this year," the 20-year-old said.

"I have taken this step in order to focus on my match fitness and ensure that I return ready to play at my highest level."