Serbia reached the Davis Cup quarterfinals when Viktor Troicki and Nenad Zimonjic beat Belgian duo Ruben Bemelmans and Steve Darcis 6-4, 6-4, 5-7, 6-4 in Saturday's doubles to take an insurmountable 3-0 lead.
Serbia had an unexpectedly tough start to the series as Troicki had to come from two sets down to beat David Goffin in Friday's opening singles match, but faced little difficulty the rest of the way.
Australian Open winner Novak Djokovic swept Olivier Rochus and the doubles team took control early before a temporary hiccup in the third set.
The result turns Sunday's reverse singles into two meaningless matches.
Serbia won despite playing without the ninth-ranked Janko Tipsarevic, who is injured. They will face the winners of the match between Brazil and the United States.