They both say they prefer the clay.
Petkovic has been rolling losing only to Bouchard at Wimbledon and Serena in Stanford but her wins aren't against very impressive players.
Stephens appears to be playing poorly losing 6 of her last 10 and hasn't won a match other than Wozniack (not Wozniacki) in nearly two months.
Petkovic is at -163 which seems like the play.
Thoughts?