Novak Djokovic handed Serbia a 1-0 lead over defending champions the Czech Republic after sweeping Radek Stepanek in the opening rubber of the Davis Cup final in Belgrade on Friday.
The world number two, and recently-crowned ATP World Tour Finals champion, beat 44th-ranked veteran Stepanek, 7-5, 6-1, 6-4, in two hours and 10 minutes.
"The 1-0 lead is very important for us," the 26-year-old Djokovic told a frantic crowd in the sold-out Belgrade Arena sitting 15,500 people.
Relying on a solid first serve throughout the rubber, Djokovic broke Stepanek's serve in game six of the first set.
But then he found himself under heavy pressure, allowing the 34-year-old Czech to win seven straight points at one moment and take the serve back.
Djokovic showed some frustration before breaking Stepanek again for a 7-5 first-set win.
Stepanek earned three break points early in the second set, but Djokovic held on to his serve and embarked on a spree to take the set, 6-1.
A single break in game nine was all Djokovic needed in the third set to finish off Stepanek.
"I am happy with the way I played. Of course I was nervous at the beginning but it was very important for us to win the first set and then I relaxed," he said.
"I served well in the important moments."
Stepanek said he would have been happier had he won the rubber, before praising Djokovic's defence.
"I tried to dictate the pace, get him into difficult situations, but he got out of them," Stepanek said.
"I gave him quite a lot of trouble in sets one and three. I failed to earn a point (by winning the rubber), but it was great tennis," he added.
Serbia's world number 117 Dusan Lajovic will now take on seventh-ranked Tomas Berdych in the second rubber of the day.
Lajovic has replaced Janko Tipsarevic, the world number 36, who has been ruled out with a heel injury.
Serbia also miss 76th-ranked Viktor Troicki due to a doping ban, while the Czechs have an interim captain for the final tie -- Vladimir Safarik, who replaced Jaroslav Navratil who was hospitalised with a pulmonary embolism.
In Saturday's doubles, Serbia's Ilija Bozoljac and Nenad Zimonjic are due to face the Czech Republic's Jan Hajek and Lukas Rosol.
But the Czechs are almost certain to bet on Berdych and Stepanek for the doubles too as the pair have lost only one of their 14 Davis Cup rubbers together since teaming up in 2007.
In Sunday's reverse singles, Djokovic will face Berdych and Lajovic will then take on Stepanek.
Serbia won their only Davis Cup title in 2010, beating France 3-2 in Belgrade.
The Czechs, playing their third final in five years, lifted the trophy last year after downing Spain 3-2 in Prague.
Previously, Czechoslovakia, which split into the Czech Republic and Slovakia in 1993, won the title in 1980.