Caroline Garcia's French Open run is over following a quarter-final defeat to Karolina Pliskova.
"I feel like I can play well on any surface," said Caroline Wozniacki after reaching the French Open quarter-finals.
Retirement does not appear an imminent concern for Maria Sharapova, who still has the desire to win top-level titles.
An elbow injury has forced Nick Kyrgios out of the Madrid Open and left him a doubt for the French Open at Roland Garros.
Dominic Thiem's win over Novak Djokovic means it is he, not the Serbian, who will take on Monte Carlo Masters champion Rafael Nadal next.
Five men's seeds crashed out on the first day of the Australian Open, but world number one Rafael Nadal was a comfortable winner.
Last year's runner-up and fifth seed Venus Williams was upstaged 6-3 7-5 by Belinda Bencic at Melbourne Park on Monday.
American 13th seed and US Open titleholder Sloane Stephens, 24, was upset 2-6 7-6 (7-2) 6-2 by Zhang Shuai on Monday.
Playing alongside grand slam champions Roger Federer and Novak Djokovic has been amazing for 16-time major winner Rafael Nadal.
He may have been comprehensively beaten in the US Open final, but Kevin Anderson was upbeat after his run in New York.
Venus Williams advances to the quarterfinals in the Italian Open after a three set battle with her British opponent.