In his first career appearance at the Australian Open, Brian Baker was forced to retire while up a set at 7-6, 1-1 on fellow American Sam Querrey due to a serious knee injury. (Update: Baker has been diagnosed with a torn meniscus and is expected to miss four months.) Baker was pulled wide to for a routine backhand. When he went to change directions, his right knee buckled. Unable to put any weight on his leg, Baker hopped to his chair to wait for the trainer. After a few minutes of evaluation that saw Baker writhe in pain, he finally shook his head, shook Querrey’s hand and waited for a wheelchair. It was heartbreaking for Baker, who could do nothing but sit with his head in his hands. Bad luck strikes again.