Radek Stepanek fought back from a set down to beat Viktor Troicki 4-6 6-2 6-4 6-4 and give the Czech Republic a 1-nil lead over Serbia in their Davis Cup semi-final.
Troicki, who stood in for Novak Djokovic after the world number two pulled out of the opening singles rubber with gastro-enteritis, was thoroughly outplayed by Stepanek after winning the opening set.
Serbia's Janko Tipsarevic faces Tomas Berdych in the second singles rubber later today.
Djokovic, who was exhausted on arrival in Belgrade from New York late after losing the U.S. Open final to Rafael Nadal, said he hoped to be fit for Saturday's doubles.
The Czechs are chasing their second successive final after losing to Spain last year while Serbia are aiming for their first after reaching the competition's top tier for the first time in 2008.