Paris - Defending champions Great Britain, Argentina and France gatecrashed their hosts' Davis Cup parties to edge closer to the semi-finals on Saturday.
Britain, playing without Wimbledon champion and world number two Andy Murray, took a 2-1 lead over 2010 winners Serbia in Belgrade.
In the second singles rubber, rescheduled from Friday due to heavy rain, Dusan Lajovic defeated James Ward 6-1, 6-3, 6-2 to pull the hosts, who are missing world number one Novak Djokovic, level.
But Jamie Murray and Dominic Inglot then beat Filip Krajinovic and Nenad Zimonjic 6-1, 6-7 (2/7), 6-3, 6-4 in the doubles to move Britain to within one win of the last four.
Krajinovic had replaced Janko Tipsarevic, who was easily defeated by Kyle Edmund 6-3, 6-4, 6-0 in the first singles rubber on Friday.
Ward can win the tie in the first reverse singles on Sunday against Tipsarevic, but if the Serb veteran wins then it will come down to a deciding match between 67th-ranked Edmund and Lajovic, the two teams' highest-ranked players.
"Constant pressure is what makes the Davis Cup a great competition and I dealt with it pretty well," said Lajovic, the world number 81.
"If I reproduce this kind of performance against Edmund, I think I have a good chance of winning."
The winners will face either Argentina or Italy in the semi-finals. Argentina are currently 2-1 in front in their last-eight tie in Pesaro.
Fabio Fognini had pulled Italy level by beating Juan Monaco 6-1, 6-1, 7-5 in a singles held over from Friday because of rain.
"I played my worst two sets of the year," admitted Monaco, back in the team after a two and a half year absence.
But Juan Martin Del Potro marked his first Davis Cup tie in four years by teaming with Guido Pella to beat Fognini and Paolo Lorenzi 6-1, 7-6 (7/4), 3-6, 3-6, 6-4.
France were also enjoying their hosts' hospitality by taking a 2-1 lead over 2012 and 2013 champions the Czech Republic in steel town Trinec.
Wimbledon champions Nicolas Mahut and Pierre-Hugues Herbert, ranked first and second in the world, beat Radek Stepanek and Lukas Rosol 6-1, 3-6, 6-3, 4-6, 6-4 in just over three hours.
"We have been getting ready for this rubber for a week," said Mahut.
"We left nothing to chance, we have been together all the time. We know each other by heart and that helps us."
The winners of that tie will face either the 32-time champions United States or Croatia for a place in the final.
In Portland, Oregon, Croatia fended off elimination as Marin Cilic and Ivan Dodig teamed up to beat the formidable US doubles duo of Bob and Mike Bryan 6-2, 2-6, 6-2, 6-4.
The home side were 2-0 up after Friday's singles.
Jack Sock stormed back from two sets down to defeat former US Open champion Cilic 4-6, 3-6, 6-3, 6-4, 6-4 before world number 12 John Isner cruised to a 6-4, 6-4, 6-3 victory over Borna Coric.
The Bryans, owners of 16 Grand Slam doubles titles, were a good bet to finish off the tie, but with Cilic stepping in to partner Dodig in place of Marin Draganja the brothers couldn't get the job done.
With Croatia still one match away from elimination at 2-1, Cilic will try to level the score when he takes on Isner in the first reverse singles on Sunday.
Cilic has won five prior encounters against Isner and was aiming to take advantage of the window he and Dodig had opened.
"Whatever happened the last two days it's behind us," Cilic said. "It's going to be definitely a tough match against John, especially on this kind of court. I'm hoping I am going to be 100 percent and I can pull out a great match."