Belgrade, Serbia – Hometown hero Novak Djokovic pulled out 0 lead in the best-of-five showdown.
David Nalbandian beat the world No. 1 Djokovic's replacement, Viktor Troicki, in four sets to give Argentina a 1-0 lead, and former U.S. Open champ Juan Martin del Potro doubled the visitors' lead by handling Janko Tipsarevic in straights.
The high-flying Djokovic was scheduled to meet the oft-injured former Wimbledon runner-up Nalbandian, but the weary star, who had been complaining about jet lag this week after capturing his first-ever U.S. Open title on Monday in New York before returning home to his beloved Serbia, cited back pain on Friday and decided that playing was not an option on Day 1.
The world No. 16 Troicki stepped in for Djokovic, only to succumb to the 74th-ranked former top-five star Nalbandian 6-4, 4-6, 6-2, 6-3 in 2 hours, 52 minutes at Belgrade Arena. Troicki fired 15 aces, but had his serve broken six times by the gritty Argentine. Nalbandian also recorded twice as many forehand winners (32-16) en route to victory.
Djokovic's availability for Sunday's reverse singles is unknown at this point.
The reigning U.S. Open, Wimbledon and Australian Open titlist Djokovic, who is an amazing 64-2 this year and has earned more than $10.6 million in prize money, led the Serbs to their first-ever Davis Cup title last year when they beat the French in the final here in Djokovic's native Belgrade.
Friday's second singles bout saw the 2009 U.S. Open titlist del Potro thump Tipsarevic 7-5, 6-3, 6-4 in 2 hours, 31 minutes. "Delpo" popped 11 aces, held his big serve throughout the rubber, and broke Tipsarevic on three occasions.
The world No. 17 del Potro is now 3-0 lifetime against the 13th-ranked Tipsarevic, including a straight-set victory in a final in Delray Beach back in February.
Tipsarevic was a surprise U.S. Open quarterfinalist last week, but lost to his good friend Djokovic in New York.
Saturday's doubles match will pit an Argentine pairing of Juan Ignacio Chela and Juan Monaco versus a Serbian duo of Tipsarevic and Nenad Zimonjic, while Sunday's reverse singles currently call for Djokovic to tangle with del Potro and Tipsarevic to take on the former top-five star Nalbandian.
Argentina, captained by Tito Vazquez, is still seeking an elusive first-ever Davis Cup championship.
Serbia is part of the former Yugoslavia, which beat Argentina in Belgrade in their lone Davis Cup matchup way back in 1964.
The winner here will face the France-Spain victor in the 2011 Davis Cup final in December.