Serena Williams made a winning return after more than a year away from tennis by beating Zarina Diyas 7-5, 6-3 to advance on Thursday at the Indian Wells Masters.
Australian Open champion Caroline Wozniacki swatted aside German Carina Witthoeft at the Qatar Open on Wednesday while an equally dominant Simona Halep made short work of Ekaterina Makarova.
The Swiss defending champion dropped his only sets of the tournament before completing a 6-2, 6-7 (5/7), 6-3, 3-6, 6-1 win over the sixth seeded Croatian in 3hr 3min.
A ruthless Roger Federer handed wounded Chung Hyeon an old-fashioned schooling before the South Korean quit with blistered feet trailing 6-1 5-2 in a damp squib of an Australian Open semi-final on Friday.
World number one Simona Halep set up an Australian Open final against Caroline Wozniacki after a thrilling 6-3, 4-6, 9-7 battle past former champion Angelique Kerber on Thursday.
Cilic, the world No. 6 and former US Open champion, won 3-6, 6-3, 6-7 (5/7), 6-2, 2-0 in 3hr 47min on Rod Laver Arena when Nadal retired in pain early in the fifth set.
The Swiss tennis player returned from six months out with knee trouble to win the Australian Open before picking up a record eighth Wimbledon crown.