Madrid - Roger Federer became the second of the world's top four to pull out of the Madrid Masters on Tuesday as he has decided to stay at home with his wife Mirka as they await the birth of their third child.
The 17-time Grand Slam champion's withdrawal comes just two days after world number two Novak Djokovic also decided not to compete in the Spanish capital due to a wrist injury.
"I've decided to withdraw from Madrid to be with my wife Mirka during these next few exciting weeks for our family," he said on his official Facebook page.
"I apologise to my fans and hope to be back in Madrid next year. I'll be training near my home, and am excited to rejoin the Tour soon!"
Federer's withdrawal could benefit Wimbledon champion Andy Murray as the Scot is now the highest seeded player left in the second quarter of the draw.
There is still plenty of star power on show in the women's Madrid Open as Li Na and Maria Sharapova moved into round three with wins on Tuesday.
Sharapova won her first tournament of the season on her return to clay in Stuttgart two weeks ago and looked in fine form as she raced through the first set 6-1.
However, McHale responded well to take the second 6-4 and led 4-1 in the decider.
Sharapova, though, wasn't to be denied by the world number 57 as she reeled off five straight games to set up a meeting with Spain's Garbine Muguruza or 2011 US Open champion Sam Stosur in the last 16.
Earlier, Australian Open champion Li had a more simple task as she swept aside fellow Chinese Zheng Jie 6-2, 6-3.
Zheng led the head-to-head record between the two 4-3 before the match, but Li has now won the last four meetings between the pair in straight sets and will face 16th seed Sloane Stephens in the next round.
Results from the fourth day of the combined ATP Madrid Masters and WTA Madrid Open on Tuesday (x denotes seeded player):
Igor Sijsling (NED) bt Tommy Haas (GER x14) 3-6, 6-1, 6-4
Kevin Anderson (RSA) bt Radek Stepanek (CZE) 3-6, 6-3, 6-4
Ernests Gulbis (LAT) bt Jerzy Janowicz (POL) 7-6 (7/5), 3-6, 6-2
Juan Monaco (ARG) bt Jurgen Melzer (AUT) 6-4, 6-3
Nicolas Almagro (ESP) bt Andrey Golubev (KAZ) 6-3, 6-7 (9/11), 7-6 (7/4)
Alexandr Dolgopolov (UKR) bt Fabio Fognini (ITA x13) 7-5, 4-6, 6-3
Lucie Safarova (CZE) bt Magdalena Rybarikova (SVK) 6-1, 6-2
Li Na (CHN x2) bt Zheng Jie (CHN) 6-2, 6-3
Maria Sharapova (RUS x8) bt Christina McHale (USA) 6-1, 4-6, 6-4
Sloane Stephens (USA x16) bt Petra Cetkovska (CZE) 6-4, 2-6, 6-3