The Spaniards grabbed their quick 2-0 lead when former world No. 1 Juan Carlos Ferrero outlasted Mikhail Kukushkin 6-1, 4-6, 7-6 (7-2), 4-6, 6-4 in 4 hours, 28 minutes and Nicolas Almagro doused Andrey Golubev 6-3, 4-6, 6-1, 6-1.
The best-of-five tie is being staged on red clay in Oviedo, where the Spaniards are playing without their top-two stars -- Australian Open runner-up Rafael Nadal and David Ferrer. As a matter of fact, Spain is missing four of its top-five players overall at Palacio Municipal de los Deportes.
Spain can clinch a victory here on Saturday when its doubles team of Marcel Granollers and Marc Lopez takes on a Kazakhstani pairing of Evgeny Korolev and Yuri Schukin.
Sunday's reverse singles currently pit Almagro against Kukushkin and the former French Open champion Ferrero versus Golubev.
The mighty Spaniards, who have won five of the last 12 Davis Cup championships, are led by first-year captain Alex Corretja, while team Kazakhstan is piloted by Yegor Shaldunov.
Spain, which beat Argentina in last year's Davis Cup finale in Seville, and Kazakhstan had never met in Davis Cup play prior to this week.
The winner here will face the Austria-Russia victor in the quarterfinals in April.