Baker held a one-set lead in the all-American clash before collapsing with a knee injury, which forced him to leave the court and in turn the tournament in a wheelchair.
After spending nearly seven years away from the tour with various problems, Querrey has admitted that he is gutted to profit from the 27-year-old's latest injury problem.
He said: "He's the last person that deserves anything like that. He does everything right, treats his body great, just trying to come back, and then something like that happens, it's just so unlucky.
"He was just going, 'I just can't believe it'. He just had his head down, just like, 'Why is this happening to me?'
"It didn't look very good, he said he kind of just felt his knee almost buckle and kind of heard like a pop or a snap. He didn't know if it was bones or a tear, but he couldn't straighten it, couldn't walk. I feel awful for him."