Singles wins Friday by Mikhail Kukushkin and Andrey Golubev gave Kazakhstan a 2-0 lead in the best-of-five series but Bemelmans and Rochus pulled off a 6-2, 6-7 (4-7), 6-3, 7-6 (7-4) win over Kukushkin and Evgeny Korolev by fighting off 16-of-18 break points they faced.
That leaves the series to be decided in Sunday's reverse singles. Kukushkin goes against David Goffin in the first match and Golubev meets Bemelmans in the final match of the series.
The winner emerging from Kazakhstan earns a spot in the April 4-6 Davis Cup quarterfinals against either Switzerland or Serbia.
Bemelmans and Rochus fended off four break points in taking the first set Saturday and faced another six in the second. The Kazakhs were able to get one break in that set and forced a tiebreaker that evened the match.
But the Belgians saved a pair of break points in the third set and again saved 5-of-6 break points in the fourth set before pulling off the win.