Top seed Rafa Nadal moved into the semi-finals of the Shanghai tennis Masters when Ivan Ljubicic became the eighth player to retire from the tournament.
The Spanish world number two had just evened the match up at 3-6 6-3 when 30-year-old Ljubicic, who had already had treatment on his left thigh, decided he could no longer continue.
Nadal faces compatriot Feliciano Lopez next, hoping to reach his first final since knee and abdominal injuries disrupted his season.
Second seeded Serb Novak Djokovic earlier beat France's Gilles Simon 6-3 2-6 6-2 to set up a semi-final against the Russian sixth seed Nikolay Davydenko, who beat the Czech Radek Stepanek 6-1 4-6 6-1.
