David Nalbandian beat Roger Federer on Thursday for the second time in less than two weeks, earning a 6-4, 7-6(3) victory in the third round of the Paris Masters.
The result evened the all-time series between the two 8-8 and ended Federer's streak of reaching the final in eight straight tournaments -- dating back to May.
"It's not easy being aggressive against him when you're 3m behind the baseline," said Federer, who lost to the Argentine in the final of the Madrid Masters on Oct. 21.
"He's got a phenomenal backhand and can dictate play from both sides," said Federer, who lost for the eighth time this season.
Guillermo Canas and Rafael Nadal have beaten Federer twice each while Novak Djokovic and Filippo Volandri have also beaten the Swiss.
Nalbandian next plays fifth seed David Ferrer of Spain, who advanced after beating 12th seed Tomas Berdych 6-4, 6-2.
After beating Federer in Madrid, Nalbandian was eliminated in the first round of last week's event in Basel, Switzerland. The week before Madrid, he was eliminated in the second round in Vienna.
"Federer's the No. 1 in the world," Nalbandian said. "You always have to be at 100 percent. I was, just like in Madrid."
Nalbandian wasted five set points by shanking balls long or into the net.
"I absolutely thought he was getting nervous," Federer said. "He has a tendency to, you know, sometimes give a second chance when you think you're down and out."
Meanwhile, Nikolay Davydenko was again accused of not putting forth his best effort, with the chair umpire criticizing the Russian's serving during a 6-2, 6-2 third-round loss to Marcos Baghdatis.
The defending champion, who was jeered during the match, finished with 10 double faults, 36 unforced errors and had his serve broken five times.
Chair umpire Cedric Mourier spoke to Davydenko during a changeover, asking him what was wrong with his serve. Davydenko responded by asking what else he could do.
"Serve like me," Mourier was heard telling Davydenko on the television broadcast. "If you serve like me, you put it in the box. That's it."
Davydenko had said on Wednesday he was hampered by a sore elbow, but he didn't give a direct answer when Baghdatis asked him what was wrong as they shook hands at the end of the match.
Last week at the St Petersburg Open, Davydenko was fined US$2,000 by the ATP for "lack of best effort" during a 1-6, 7-5, 6-1 loss to Marin Cilic.
"I cannot serve," Davydenko said of Thursday's match. "That was happening in St Petersburg. I don't have pain really. I have no pain in my elbow. I need to find what's the reason I cannot really serve."
ATP spokesman Nicola Arzani said no action will be taken against Davydenko.
Meanwhile, second seed Rafael Nadal, eighth seed Tommy Robredo, Ferrer and 10th seed Richard Gasquet of France all advanced in straight sets.
Gasquet next meets 15th seed Andy Murray, who beat Fabrice Santoro 6-4, 6-2 to retain his chances for Shanghai.
Davenport eases into quarters
Lindsay Davenport advanced to the Bell Challenge quarter-finals on Thursday night, routing Canada's Aleksandra Wozniak 6-1, 6-0.
Playing her third singles tournament since returning after giving birth to her first child in June, she will face France's Stephanie Foretz, who beat Sweden's Sofia Arvidsson 1-6, 6-2, 7-5.
Davenport, a three-time Gland Slam champion, returned to play in September, winning the Bali Open and reaching the semi-finals in the China Open.