Ash Barty's coach has sensationally drawn a line through his superstar charge's chances of completing a coveted career grand slam unless US Open officials change the balls.
Barty's watershed Australian Open triumph on Saturday earned the world No.1 her third career major following French Open glory in 2019 and magical Wimbledon ride last year.
After defeating American Danielle Collins 6-3 7-6 (7-2) in a thrilling Melbourne Park decider, the US Open is now the only remaining slam to elude Barty.
