Russia’s Nikolay Davydenko retired from his Malaysian Open quarter-final against Kei Nishikori on Friday after suffering a muscle injury in his left leg.

The former world number three and winner of the inaugural Malaysian Open in 2009 had lost the first set against the third seeded Japanese 6-4 before calling it quits.

Davydenko, who has dropped to number 44 in the world, first pulled up injured in the eighth game of the first set. He called for a medical time-out and only played another two games before losing that set.

He then decided to quit the tournament, handing Nishikori a semi-final berth. In the semis, the 22-year-old, who at number 17 is the highest ranked Asian in the world, will meet second seed Juan Monaco of Argentina.

“Now that I have qualified for the semi-finals, my thoughts are on my opponent and close friend Monaco,” Nishikori said.

“I have been practising with him since we arrived in Malaysia. I expect a difficult match as we know each other’s game very well … He likes to play from the baseline so I will have to adjust my game plan accordingly.”

In an earlier match, world number 11 Monaco easily defeated Canadian Vasek Pospisil 6-3 6-4.

Seventh seed Julien Benneteau of France also smashed Alejandro Falla of Colombia 6-2 6-2.

Friday’s last quarter-final will see world number five and top seed David Ferrer of Spain play against Dutchman Igor Sijsling.