Russia [Images] benefited from Novak Djokovic's misfortune to sneak into the quarter-finals of the Davis Cup on Sunday.

The Serbian, who had been suffering from flu symptoms over the past week, was leading Nikolay Davydenko 6-4, 6-3, 4-6 in the first reverse singles when he abruptly retired to hand Russia an unbeatable 3-1 lead in the first-round tie in Moscow [Images].

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"I stopped because I didn't want to risk my health," the Australian Open champion told reporters.

"I was feeling very dizzy. I was losing a lot of energy. It's not easy to play when you have a virus infection."

Viktor Troicki beat Dmitry Tursunov [Images] 7-6, 4-6, 6-3 in the final rubber to narrow Russia's winning margin to 3-2.

Djokovic's plight enabled Russia, champions in 2006 and finalists last year, to preserve their unbeaten home streak to 15 ties.

They will get a chance to extend that run when they host the Czech Republic, 3-2 winners over Belgium, in April.

In Tel Aviv, Sweden's Jonas Bjorkman shed his tag as simply a doubles specialist when he overcame a nightmare start to stifle Israeli hopes with a 0-6, 6-4, 6-3, 7-6 win over Harel Levy.

Bjorkman's win gave Sweden a 3-2 win and secured the seven-times winners a quarter-final trip to Argentina.

Philipp Kohlschreiber beat Lee Hyung-taik 6-0, 4-6, 6-1, 7-6 in Braunschweig to complete a heroic personal effort and set Germany [Images] up for a 3-2 win over South Korea.

Kohlschreiber's victory on an awkward indoor clay court was his third success over the weekend. Next up for them will be Spain.

"I'm delighted with the way it all went," said Kohlschreiber, Germany's number one in the absence of the injured Tommy Haas. "It's been a super week for me."

'GOOD REFLEXES'

In the only world group contest to go into a live fifth rubber, Bjorkman was made to feel all of his 35 years as he watched the first set flash by in a blur.

But it was not long before he remembered his own mantra.

"I'm fitter than ever, I have been changing diapers really well so my reflexes are very good," Bjorkman, who became a father for the second time last month, said before the tie.

Those skills proved to be handy in the second set when he started to chip and charge to the net and kept the points short with his serve-and-volley tactics against Levy.

"I started off pretty badly, I felt that it couldn't get much worse... but in a five-setter you always have the chance to get back into the match," Bjorkman said on Sunday.

Holders United States, who next meet France [Images], completed a 4-1 win over Austria. The only success for the hosts in Vienna was when Mike Bryan limped off court with a strained hamstring after just one set and a game against Stefan Koubek.

Romania suffered the ignominy of being one of only two nations to suffer 5-0 drubbings. While they were routed by France, Peru failed to win even a set against Spain in Lima.

Jamie Baker spared Britain from a whitewash against Argentina after defeating Agustin Calleri 7-6, 6-4 in the final dead rubber in Buenos Aires.

Argentina, runners-up in 2006, had already secured their place in the last eight on Saturday after taking a 3-0 winning lead but fell one match short of completing a rout.

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