**Novak Djokovic saw off Sam Querrey in four sets to put Serbia in command against the US after day one of their Davis Cup World Group tie in Belgrade.**The world number two gave his nation a 2-0 lead with a 6-2 7-6 (7-4) 2-6 6-3 victory in front of 20,000 spectators.
Viktor Troicki had earlier battled past John Isner 7-6 (7-4) 6-7 (5-7) 7-5 6-4 in a tight opening singles rubber.
Reigning champions Spain were held to 1-1 by Switzerland in Logrono, with Rafael Nadal and Roger Federer absent.
The holders remained strong favourites on their preferred surface of clay despite being without Nadal, Fernando Verdasco and Juan Carlos Ferrero, but Stanislas Wawrinka gave the Swiss an early lead as he beat Nicolas Almagro 3-6 6-4 3-6 7-5 6-3.
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David Ferrer then calmed Spanish nerves as he eased past Marco Chiudinelli 6-2 7-6 (7-5) 6-1.
Sweden and Argentina also shared the spoils on the opening day in Stockholm, with Robin Soderling beating Eduardo Schwank 6-1 7-6 (7-0) 7-5 before Leonardo Mayer saw off Joachim Johansson 5-7 6-3 7-5.
France, Russia, Croatia and the Czech Republic all moved within sight of the quarter-finals by taking 2-0 leads.
Djokovic needed five match points to finally secure a convincing lead for Serbia after three hours and 21 minutes.
“I expected a great fight and I had some fears in terms of my physical condition and the quick return to clay courts,” he said.
“Querrey played better and better as the match progressed and he gave me a lot of trouble. Despite our big 2-0 lead, nothing is decided yet.”
Chile begin their tie against Israel in Coquimbo on Saturday, a day late following the earthquake in the country.