PARIS (AFP) - Rafael Nadal led Spain to a 4-1 Davis Cup win over France on Sunday, and a final date with Argentina, but there were tears for US Open champion Novak Djokovic whose injury-forced retirement saw defending champions Serbia slump 3-2 to the South Americans. As Nadal brushed aside fatigue from his US Open final loss to Djokovic to win two of his sides semi-final rubbers, the tearful Serb collapsed on court in agony in Belgrade with back pain less than a week after his Flushing Meadows triumph. Nadal slayed Frances Jo-Wilfried Tsonga 6-0, 6-2, 6-4 in Cordobas bullring to secure the winning point after the world number two thrashed Richard Gasquet 6-3, 6-0, 6-1 in Fridays opening rubber. Its really unbelieveable, the feelings are very, very emotional here today, said Nadal, who has a 18-1 win-loss record in Davis Cup. Fernando Verdasco completed the rout for the hosts when he beat Gasquet 6-2, 6-1 in the final dead rubber. In Belgrade, Djokovic admitted he had been carrying a back injury from the US Open as he retired while trailing 7-6 (7/5), 3-0 in the days first reverse singles to Juan Martin Del Potro. Djokovic, who missed the opening days play with a back injury, replaced Viktor Troicki in Sundays line-up as captain Bogdan Obradovic tried to get the champions back into the tie in which they trailed 2-1 overnight. Of course I am very disappointed that the match ended this way, said the world number one. I tried, but it did not work, I was not even 60 percent ready, but we have accepted that risk although we knew that my injury could worsen, added Djokovic, who had needed treatment on his back during his US Open final win. It was only the third defeat in 67 matches this season for the Serb and his second retirement. Djokovics absence on Friday had seen Serbia slump 2-0 before Troicki and Nenad Zimonjic defeated Juan Ignacio Chela and Juan Monaco 7-6 (7/4), 6-4, 6-2 on Saturday to keep the hosts bid alive. In the dead rubber, Monaco, who replaced David Nalbandian, retired after the first set against Janko Tipsarevic, which the Serbian player had won with 6-2. Argentina will travel to Spain for the December 2-4 final as they bid to win their first Davis Cup trophy after finishing runners-up in 1981, 2006 and 2008. The Nadal-inspired Spanish, who are looking unbeatable on clay, are bidding for their fifth title after 2000, 2004, 2008, 2009. David Ferrer defeated Gilles Simon 6-1, 6-4, 6-1 on Friday before Tsonga and Michael Llodra kept Frances hopes alive on Saturday when they beat Spanish doubles duo Feliciano Lopez and Fernando Verdasco 6-1, 6-2, 6-0.