Mario Ancic and Ivan Ljubicic kept their doubles record spotless this season with a 7-6 (7/5), 6-3, 7-6 (7/5) victory over Slovaks Dominik Hrbaty and Michal Mertinak to put Croatia into 2-1 command at the Davis Cup final.
World number nine Ljubicic and his 22nd-ranked compatriot left the visitors needing only one reverse singles victory in Bratislava on Sunday to lift an historic first-ever Davis Cup trophy for the nation.
Ancic and Ljubicic have now won all four of their Davis Cup doubles rubbers this season, clinching victory in a third-set tiebreaker after 2hr 47min.
Slovakia, playing for the fourth time at home during the 2005 campaign, can write a record of their own if the squad led by Hrbaty can miraculously turn the tide with a pair of singles wins on the concluding day.
The nation which wins will become the 12th to own a Davis Cup title after the unedited battle of first-time finalists.
As expected, Hrbaty was called into action by coach Miloslav Mecir just a few hours before the doubles start, with Karol Beck suffering from both a knee injury and allegations of a positive drugs test at September's semi-final against Argentina here.
Ljubicic's part in the doubles victory put him within one win of the all-time record of a dozen Davis victories in a season achieved by John McEnroe in 1982.
The first set, played in the hothouse atmosphere of the tiny 4,100-capacity Sibamac arena, featured drama from the start, with Ancic requiring eight minutes to hold serve in the opening game with his side fending off a pair of break points.
The scenario was further complicated by a run of four consecutive service breaks, ending when Ljubicic held to put Croatia into a 6-5 lead.
With the set eventually moving to a tiebreaker, it was the world number nine who finally wrapped it up after 61 minutes, firing down the side's fifth ace to secure the set for the visitors.
Hrbaty, home hero in Friday's singles fightback over Ancic, proved to be the weak link in the second set.
The Slovak twice lost serve in a quick-fire 36-minute encounter, with his volley wide last Ljubicic handing over the second set to the Croatians.
