The Czech Republic's Tomas Berdych beat Dusan Lajovic of Serbia 6-3 6-4 6-3 in Friday's second singles to level the Davis Cup final at 1-1 at the end of day one in Belgrade.
Novak Djokovic had put the hosts 1-0 up with a 7-5 6-1 6-4 victory over Radek Stepanek, but world No 117 Lajovic was always unlikely to double Serbia's lead against world No 7 Berdych.
Lajovic had been drafted in as a late replacement for the injured Janko Tipsarevic and gave it his all in front of a passionate 17,000-plus crowd at the Kombank Arena.
But despite all his efforts he could not even force a break point against the composed and efficient display of Berdych.
Five times Lajovic got to 0-30 on the Berdych serve and each time the Czech man won the next four points to hold.
Berdych broke in the eighth game of the opening set as he crunched a backhand winner, before setting up the second set by taking the fifth game against the feed with a winning forehand.
The third set was over even quicker as he stole serve in the opening game with a deft drop shot and then wrapped things up by breaking for a fourth time in total.
Earlier, Djokovic had to work hard to take the opening set against Stepanek as he seemed nervy in front of a noisily passionate home crowd, but after the world No 2 saved three break points early in the second set he gradually took control.
Having come out on top in several long rallies in the opening stages, Stepanek faded as his opponent began finding his range with destructive baseline shots.
Djokovic broke the Czech in the ninth game of the third set and then held serve to seal the match and draw a standing ovation from the home fans.
"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," Djokovic said. "I served well in the important moments."
Stepanek praised Djokovic's defence, adding: "I tried to dictate the pace, get him into difficult situations, but he got out of them.
"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."
There will be a doubles on Saturday and two reverse singles on Sunday.