MADRID (AFP) - Novak Djokovic moved into the semi-finals of the Madrid Masters on Friday (May 12) without hitting a ball as Kei Nishikori withdrew with a wrist injury, tournament organisers said.
The world number eight missed the Barcelona Open late last month due to the recurring problem.
Nishikori is now also a major doubt for the Rome Masters next week with 10 days to go until the start of the French Open.
"I will plan to play Rome, but we'll see," said the Japanese.
"I cannot promise to play or pull out right now.
"(The) French is more important."
Djokovic will either renew his rivalry with Rafael Nadal or face Belgium's David Goffin in the last four on Saturday.
On the other side of the draw Uruguayan Pablo Cuevas advanced to his first ever Masters series semi-final by outlasting German wonder kid Alexander Zverev 3-6, 6-0, 6-4.
Zverev had been on a seven-match victory streak after winning his second title of the season in Munich last week.
However, after a bright start from the 20-year-old, tiredness kicked in as Cuevas, backed by a fervent support including Atletico Madrid duo Diego Godin and Antoine Griezmann, roared back to win the second set 6-0.
And Cuevas landed the only break in the final game of the deciding set when Zverev fired wide to set up a semi-final against Dominic Thiem or Andy Murray's conqueror Borna Coric.
In the Women's Madrid Open, defending champion Simona Halep cruised back into the final for the third time in four years with a 6-2, 6-3 success over Latvia's Anastasija Sevastova.
Halep also thrashed the world number 22 two weeks ago in Stuttgart and there was never any danger of an upset as the Romanian reeled off five straight games to close out the opening set.
Sevastova hinted at a fightback early in the second as she got out to a 3-0 lead.
But Halep, who is also into the semi-finals of the women's doubles with compatriot Irina-Camelia Begu, showed no signs of lacking in energy as she bounced back in emphatic fashion to win the last six games for the loss of just 14 points.
Halep with face in-form Frenchwoman Kristina Mladenovic or Svetlana Kuznetsova in Saturday's final.