Days after Victoria Azarenka sang 'Happy Birthday' for her 'best friend' Gael Monfils — who celebrated his 28th birthday on Monday — at the Arthur Ashe Stadium, her close pal Caroline Wozniacki has some friendly advice for her: Shut up!


Caroline Wozniacki and Victoria Azarenka 

Wozniacki, who beat Sara Errani on Tuesday, said after her match, "Vika, you shouldn't audition for The Voice. That was a screech."