World No. 59 scores 6-3, 3-6, 6-4 win, will face qualifier Vickery next. Petkovic also advances.
"I injured myself yesterday during practice...I will have to stay out of competition for at least two to three weeks," said world No. 2.
No. 4 seed beats Querrey for first time since 2008, 6-4, 5-7, 6-4.
"A lot of the other strokes I think he does a lot better than I did. But I`ll give myself a bit of favor with my backhand," says Hall of Famer.
World No. 26 is out for season after fourth shoulder surgery.
What's really ailing the world No. 1 Serena Williams?
Reviewing the big breakthroughs, altered allegiances and tool-time label on the tours.
You haven't competed in tennis until you've played mixed doubles.
The pros and cons of Big John. Plus: Saturday previews and Delpo hits backhands.