No. 21-seeded Philipp Kohlschreiber, followed by No. 13 John Isner, were among five players who dropped out of the Australian Open on Tuesday, joining No. 12 seed Tommy Haas and two other players who withdrew Monday.
Former US Open champions Juan Martin del Potro of Argentina and Samantha Stosur of Australia rallied to win their second-round matches against tough French opponents Wednesday at Australian Open warm-up tournaments.