BELGRADE, Serbia, March 6 (UPI) -- Americans Bob Bryan and John Isner teamed for a four-set victory Saturday, keeping Serbia from clinching the first-round Davis Cup series.
Bryan and Isner claimed a tight 7-6 (10-8), 5-7, 7-6 (10-8), 6-3 win over Serbians Janko Tipsarevic and Nenad Zimonjic that cut Serbia's lead to 2-1 in the best-of-five series.
The United States needs to win both singles matches Sunday or Serbia will earn the Davis Cup quarterfinals spot against Croatia, which won its first-round series against Ecuador.
Bryan and his twin brother Mike comprise the No. 1 doubles team in the world but Isner was a late substitute for Mike Bryan, who contracted food poisoning Saturday.
Still the Americans only dropped serve once -- the game that cost them the second set -- but took the two long tie-breakers and cashed in two service breaks to take the fourth set and the match.
Serbia would advance in the Davis Cup bracket with a win in either of Sunday's singles.
Isner, who lost two tie-breakers in a three-set loss Friday to Viktor Troicki, goes against world No. 2 Novak Djokovic in the first match Sunday. Troicki battles Sam Querrey in the final match of the series.
