Russia's Nikolay Davydenko beat Argentine Gaston Gaudio 6-3 6-4 to close in on a spot in the last four at the season-ending Masters Cup on Wednesday.
World number seven Davydenko frustrated Gaudio with his pin-point accuracy to win his second straight match at the $4.45 million event in Shanghai.
Gaudio, who won last year's French Open, slipped to 1-1 following his victory over countryman Mariano Puerta on Monday and must now win his final Gold Group match to advance.
Davydenko had thrashed Andre Agassi 6-4 6-2 in the first match of his Masters Cup debut, after which the American pulled out of the tournament citing an ankle injury.
French Open champion Rafael Nadal withdrew shortly before Agassi to join tournament no-shows Andy Roddick, Marat Safin and Lleyton Hewitt on the sidelines.
Replacements Puerta and Chile's Fernando Gonzalez meet in Wednesday's second match at Qi Zhong stadium.
