Djokovic moves into Masters Cup semis

THE ASSOCIATED PRESS SHANGHAI, China -- Confused and jittery after failing to win a game in the second set, Novak Djokovic rallied past Nikolay Davydenko 7-6 (3), 0-6, 7-5 Tuesday to reach the semifinals of the season-ending Masters Cup. In the day's other round-robin match, Juan Martin del Potro of Argentina defeated Jo-Wilfried Tsonga of France 7-6 (4), 7-6 (5) in a meeting between promising players making Masters Cup debuts. Tsonga sat out three months with a knee injury this year and had to win the Paris Masters nine days ago to qualify for this showcase for the game's top eight players. Del Potro was ranked No. 65 in July before a 23-match winning streak vaulted him to No. 8. Davydenko will play Del Potro on Thursday with a semifinal berth at stake. "You know it's your last chance," Davydenko said. "If I win, I can qualify. If not, then I go on holiday." Del Potro's holiday will be delayed at least another week. He will play for Argentina in the Davis Cup final Nov. 21-23 against a Spanish team that will be without top-ranked Rafael Nadal because of a sore knee. "For all tennis players, it's like a dream to be here," Del Potro said. "But also next week it will be another dream." Roger Federer and Andy Roddick, who lost their first matches in the Red Group, face each other Wednesday. Andy Murray and Gilles Simon will also play. Also Wednesday, Toronto's Daniel Nestor and Nenad Zimonjic of Serbia are scheduled to play Jonas Bjorkman of Sweden and Kevin Ullyett of Zimbabwe. Nestor and Zimonjic won their opening round-robin match Monday. Djokovic ran his record to 2-0 in the Gold Group and eliminated Tsonga. Djokovic won only nine points in the second set. Davydenko, who fell to 1-1, said he never saw the third-ranked Serb play so poorly. "I had a very unexplainable lapse. I just wasn't myself," Djokovic said. "It was very hard to come back. I was really nervous." The last time he failed to win a game in a set came against Richard Gasquet at the Estoril Open final in April 2007. He won that match, too. Davydenko yielded only four points in his first four service games, leaving Djokovic frustrated and looking toward his fans. Then Davydenko self-destructed. Serving for the first set at 5-4, the Russian double-faulted at 30-30 and sent a forehand wide to even the match. In the tiebreaker, Davydenko handed the first four points to Djokovic with three forehand errors and a double-fault, then double-faulted again on set point. Djokovic recovered in the third set. Serving at 5-5, 40-30, Davydenko grimaced after hitting a backhand volley wide, then sent two forehands long for the break. Djokovic held to finish the match. Del Potro, at 20 the youngest player in the field, has had a sore toe since the U.S. Open. He said he was trying to win while also conserving energy for Davis Cup, but Tsonga's power sent him lunging from side to side. Tsonga had the linesmen ducking with 10 aces in his first four service games. But inconsistency -- and solid play from Del Potro -- undid the Frenchman. Tsonga led 3-1 in the first tiebreaker, but Del Potro ran off six of the next seven points to finish the set. In the second tiebreaker, Del Potro ripped a backhand winner on the run to pull ahead 4-2. An overhead winner set up triple match point at 6-3. Tsonga hit an ace and a service winner before netting a forehand to end the match. "I know he played better than me in the tiebreak," Tsonga said. "I miss some easy balls, and that's it."