Players struggled with cramp and injuries on the second day of the Australian Open on Monday, headlined by the retirement of seventh seed Felix Auger-Aliassime while his compatriot Marina Stakusic needed a wheelchair to leave the court.
Third-seeded Jessica Pegula and fourth-seeded Jasmine Paolini of Italy were knocked out during second-round play Wednesday on the grass at the Berlin Open.
Third seed Andrey Rublev suffered a first round exit after his Qatar Open title, losing to qualifier Quentin Halys 3-6, 6-4, 7-6(5) at the Dubai Open on Tuesday.
Eight-time Wimbledon champion Roger Federer, who turns 40 this year, takes on Frenchman Adrian Mannarino in round one.