(CNN) -- Giant Croatian Ivo Karlovic served a world record 78 aces but could not stop the Czech Republic taking a 2-0 lead after a marathon opening day of the Davis Cup semifinal in Porec.
Ivo Karlovic found himself on the losing side despite smashing the world record for aces served.
The 6' 10" Karlovic was defeated in the opening singles rubber by Radek Stepanek, who won 6-7 (5-7) 7-6 (7-5) 7-6 (8-6) 6-7 (2-7) 16-14 in five hours and 59 minutes -- the fourth-longest match in the tournament's history.
The 82 games played made it the equal-highest number in the Davis Cup since the introduction of tiebreaks in 1989.
World No. 31 Karlovic smashed the previous Davis Cup record of 47 aces, and then soon went past the world best mark of 55.
However, he squandered four match-points in the epic final set in a clash that saw two service breaks in the first three games but not another one until the 29th game of the decider.
"The crowd was amazing, we had a lot of fans and it was like playing at home," Stepanek told the Davis Cup Web site.
"I was very surprised. The Croatian fans were great as well. They gave the players lots of support and huge atmosphere. It was just an honor -- that's why we play tennis, because of fans like this."
In the second match late on Friday, which lasted three hours and 48 minutes on the indoor clay surface, Tomas Berdych beat U.S. Open quarterfinalist Marin Cilic 6-3 6-3 3-6 4-6 6-3.
It left the Czechs poised to reach the final for the first time since winning the event in 1980.
Saturday's doubles will prove key, with the respective captains deciding to change their original pairings.
Croatia had initially opted for Roko Karanusic and Lovro Zovko, but instead went with Cilic and Zovko.
The Czechs replaced Lukas Dlouhy and Jan Hernych with their winning singles duo of Berdych and Stepanek.
If the Czechs do get through, they seem likely to face Spain in the final after the defending champions took a 2-0 lead against Israel at home on clay near Murcia.