Serbians upset Bryan brothers

Ilija Bozoljac and Nenad Zimonjic earned Serbia a potentially crucial lead in their Davis Cup quarter-final against the United States.

World number one Novak Djokovic will attempt to convert Serbia's 2-1 lead in the match to victory when he takes on Sam Querrey in the first billed singles on Sunday, at the Taco Bell Arena in Boise, Idaho.

Should Querrey cause an upset by toppling Djokovic, the match would come down to a final rubber between John Isner and Victor Troicki.

Mike and Bob Byran, the world's leading doubles team, came from two sets down against Bozoljac and Zimonjic to force a decider, and for 26 games there was no way past the serve.

But almost out of nowhere the Serbian duo forced two break points against the US serve at 13-13, and they took the second to give themselves a chance to serve for the win.

It looked like lightning might strike twice when the Bryans forced 15-40 in the next game, but back came their opponents to take it to deuce with a pair of Zimonjic aces. And after spurning a first match point they made no mistake second time round.

The 7-6 (7/5) 7-6 (7/1) 5-7 4-6 15-13 victory came in four hours and 23 minutes of brutal tennis, with Djokovic roaring on his team-mates from the side of the court.

Canada captured a 2-1 lead in their match against Italy in Vancouver, where the doubles was just as dramatic as it was in Idaho, following the same pattern all the way.

Daniel Nestor and Vasek Pospisil earned a two-set lead that was recovered by the Italian pair of Daniele Bracciali and Fabio Fognini, before Nestor and Pospisil won another 28-game final set.

Eventually Nestor and Pospisil were able to celebrate a 6-3 6-4 3-6 3-6 15-13 victory in four hours and 27 minutes.

Milos Raonic will look to settle the tie in Canada's favour on Sunday when he takes on Andreas Seppi in the day's opening rubber. Pospisil is due to play Fognini in the final rubber of the match.

David Nalbandian and Horacio Zeballos gave Argentina a 2-1 lead going into the final day of their quarter-final against France.

Nalbandian and Zeballos beat Julien Benneteau and Michael Llodra 3-6 7-6 (7/3) 7-5 6-3.

Juan Monaco is nominated to face Jo-Wilfried Tsonga in the first of the reverse singles rubbers, with Carlos Berlocq and Gilles Simon due to play the final rubber.

In Astana, Kazakhstan narrowed the Czech Republic's lead to 2-1 in their tie as Yuriy Schukin and Andrey Golubev claimed a 7-6 (7/2) 6-4 6-3 win over Radek Stepanek and Jan Hajek.

In the singles, Lukas Rosol is scheduled to face Mikhail Kukushkin, before Hajek meets Golubev.