Argentine David Nalbandian thrashed Croatia's Ivan Ljubicic 6-2, 6-2 to reach the semi-finals of the season-ending Masters Cup on Thursday.
World number one Roger Federer and Nikolay Davydenko of Russia have already booked their places in the last four at the $4.45 million Shanghai event.
Argentine Gaston Gaudio plays Chile's Fernando Gonzalez on Friday for the remaining semi-final spot.
Nalbandian was beaten by Federer in his opening Red Group match but was in inspired form against Ljubicic, storming to a 5-0 lead before taking the first set in 32 minutes.
The world number 12 secured a double break in the second set with a superb forehand pass on the run as Ljubicic's game fell to pieces.
Nalbandian closed out a one-sided match with a kicking serve wide that Ljubicic pushed tamely out after just 67 minutes.
Ljubicic, who also lost to Federer, had been trying to become the first Croatian to reach the semi-finals of the year-ending championships since Goran Ivanisevic in 1996.
Federer plays Argentine Guillermo Coria in the last match on Thursday. Coria is winless after his first two group matches.