From the Murray brothers' rescue act to Rafael Nadal taking Spain to the World Group and Kei Nishikori leading Japan's return to the top, here is a roundup of all the Davis Cup action from Saturday.
Great Britain vs Argentina
Andy and Jamie Murray kept Britain alive in their Davis Cup semi-final against Argentina's Juan Martin del Potro and Leonardo Mayer, winning the doubles match in four sets to reduce the deficit to 2-1 on Saturday.
The Murray brothers beat del Potro and Mayer 6-1, 3-6, 6-4, 6-4 in front of a rowdy crowd in Glasgow.
The semi-final is extended to the reverse singles on Sunday, when Andy Murray will play Guido Pella and del Potro will face play Kyle Edmund.
Del Potro and Murray were back on court after an epic 5-hour, 7-minute opening singles on Friday, won by del Potro in five sets. Del Potro wasn't slated to play in the doubles and was a surprise late change by Argentina captain Daniel Orsanic, especially given the player's injury problems in recent years.
"As soon as we heard Juan Martin was coming in, they showed their cards, that they wanted to finish the tie today," Britain captain Leon Smith.
The Murrays have a 6-0 record in Davis Cup doubles.
The winner will play either Croatia or France in the final — and it's likely to come down to the final match, with Murray a heavy favorite to make it 2-2.
Croatia vs France
Marin Cilic and Ivan Dodig put Croatia 2-1 ahead in their Davis Cup semi-final against France by upsetting top-ranked doubles pair Nicolas Mahut and Pierre-Hugues Herbert 7-6 (6), 5-7, 7-6 (6), 6-3 on Saturday.
Cilic, who won his singles tie on Friday, replaced Marin Draganja and it proved to be an inspired choice. Herbert, the more inexperienced of France's doubles pairing, sent his volley into the net to hand Croatia an unexpected victory at the Kresimir Cosic Hall in Zadar.
Croatia's performance stunned France's captain Yannick Noah. "I didn't expect to see Dodig playing at this level," Noah said. "Croatia is in a good position because Marin is playing good tennis. They have been better than us over the first two days (and) we haven't found the keys (to victory) yet."
Richard Gasquet now must beat Cilic in the first of Sunday's reverse singles to keep France alive. Gasquet leads Cilic, the 2014 US Open champion, 2-1 in their career head-to-head and that makes Cilic wary. "It's always difficult against him," Cilic said. "But in my two defeats I remember having a lot of break-point chances."
Pouille is then scheduled to face Borna Coric in what could be Sunday's deciding rubber. Coric won their only previous meeting, which was in straight sets at Indian Wells in March.
The winner plays Britain or Argentina in the final in November.
India vs Spain
Tennis star Rafael Nadal and Marc Lopez clinched the Davis Cup World Group play-off tie for Spain with a hard-fought doubles win over India in New Delhi.
Nadal and Lopez, who won the doubles gold at the recent Rio Olympics, helped Spain take an unassailable 3-0 lead to enter the elite group after a two-year gap.
World number four Nadal shrugged off early rustiness as the Spanish pair served past the Indian duo of Leander Paes and Saketh Myneni 4-6, 7-6, 6-4, 6-4 in three hours and 23 minutes.
Nadal missed the opening singles match on Friday following a reported stomach ache as Feliciano Lopez and David Ferrer put Spain in firm control of the tie with their respective wins.
But the 14-time Grand Slam winner made his presence felt in the doubles encounter at Delhi's RK Khanna Tennis Stadium. Nadal's early struggle with his game saw the visitors lose the first set after being broken twice by an inspired home pair who had the raucous crowd behind them.
The Spanish duo was also run close in the second set, but a crucial break in the 10th game proved to be a turning point for the visitors. The tie-break win was enough to get the best out of Nadal, who showed flashes of his brilliance to entertain the capacity crowd.
Paes and Myneni fought valiantly against their opponents, never allowing the Spanish pair to breathe easy in the marathon battle. The 43-year-old Paes, with his neat serve and volley, showed why he is known to be a dangerous doubles player.
Left-handed Nadal, who was guilty of committing a lot of unforced errors in the first two sets, attacked the net with great success as Spain dominated the final two.
Marc Lopez, placed 15th in doubles ranking, complimented Nadal's attacking style with his good baseline play.
Spain, who bowed out of the World Group after a first-round loss against Germany in 2014, now head into the elite round of matches.
The 'dead' reverse singles will be played on Sunday.
Poland vs Germany:
Poland's impressive fight-back over Germany in Saturday's doubles keeps their chances alive at 2-1 down in the Davis Cup World Group play-off.
Marcin Matkowski and Lukasz Kubot battled back superbly from losing the first two sets to claim a 6-7 (5/7), 4-6, 6-3, 6-4, 6-2 victory over Daniel Brands and Daniel Masur in rain-hit Berlin.
After Jan-Lennard Struff and Florian Mayer won their singles rubbers at Rot-Weiss Tennis Club, a third triumph would have given Germany victory, as the start of the doubles match was delayed by heavy rain.
Under dark skies, Poland looked set for an early trip home after dropping the opening sets, but Kubot and Matkowski powered back for an unlikely win to maintain their country's interest with a victory after three hours, 39 minutes.
Sunday's last two rubbers see Mayer play Kamil Majchrzak and Struff face Hubert Hurkacz.
Japan vs Ukraine
Kei Nishikori and Yuichi Sugita beat Artem Smirnov and Sergiy Stakhovsky 6-3, 6-0, 6-3 as Japan won its Davis Cup World Group playoff 3-0 against Ukraine on Saturday.
The Japanese duo was in control from the outset and converted nine of 15 break point opportunities.
With the win, Japan secured its place in the World Group in 2017.
Yoshihito Nishioka and Taro Daniel gave Japan a commanding 2-0 lead with wins in singles on Friday.
Ukraine was bidding for its first appearance in the World Group but will remain in the Europe/Africa Zone Group 1 next year.
Australia vs Slovakia
Doubles pair Sam Groth and John Peers beat Slovakia's Andrej Martin and Igor Zelenay 6-4, 6-2, 6-7 (3), 7-6 (2) on Saturday to clinch Australia's Davis Cup World Group playoff 3-0.
Slovakia saved a match point in the 12th game of the third set before winning the tiebreaker. But Australia dominated the fourth-set tiebreaker, winning the first five points.
The win with new captain Lleyton Hewitt in charge ensured Australia, a first-round loser to the United States in February, will remain in the elite group of 16 countries for 2017.
On Friday, Nick Kyrgios and Bernard Tomic had straight-set singles victories on the grass court at Sydney Olympic Park. Kyrgios opened with a 6-3, 6-2, 6-4 win over Martin and Tomic beat Jozef Kovalik 7-6 (5) 6-4, 6-4.
Here's a look at all the major results
Semifinals: Winners to World Group Final, 25-27 November
Argentina 2, Britain 1
Juan Martin del Potro, Argentina, beat Andy Murray, Britain, 6-4, 5-7, 6-7 (5), 6-3, 6-4.
Guido Pella, Argentina, beat Kyle Edmund, Britain, 6-7 (5), 6-4, 6-3, 6-2.
Andy and Jamie Murray, Britain, beat Federico Delbonis and Leonardo Mayer, Argentina, 6-1, 3-6, 6-4, 6-4.
Croatia 2, France 1
Richard Gasquet, France, beat Borna Coric, Croatia, 6-2, 7-6 (5), 6-1.
Marin Cilic, Croatia, beat Lucas Pouille, France, 6-1, 7-6 (4), 2-6, 6-2.
Ivan Dodig and Marin Draganja, Croatia, beat Pierre-Hugues Herbert and Nicolas Mahut, France, 7-6 (6), 5-7, 7-6 (6), 6-3.
Playoffs: Winners to 2017 World Group; losers to 2017 Zonal I Groups
Switzerland 2, Uzbekistan 1
Denis Istomin, Uzbekistan, beat Antoine Bellier, Switzerland, 6-3, 6-2, 6-4.
Henri Laaksonen, Switzerland, beat Farrukh Dustov, Uzbekistan, 6-2, 6-2, 6-2
Adrien Bossel and Johan Nikles, Switzerland, beat Farrukh Dustov and Denis Istomin, Uzbekistan, 6-4, 6-2, 7-6 (2).
Belgium 3, Brazil 0
David Goffin, Belgium, beat Thiago Monteiro, Brazil, 6-2, 6-2, 6-0.
Steve Darcis, Belgium, beat Thomaz Bellucci, Brazil, 6-7 (5), 6-1, 6-3, 6-3.
Ruben Bemelmans and Joris De Loore, Belgium, beat Marcelo Melo and Bruno Soares, Brazil, 3-6, 7-6 (5), 4-6, 6-4, 6-4.
Australia 3, Slovakia 0
Nick Kyrgios, Australia, beat Andrej Martin, Slovakia, 6-3, 6-2, 6-4.
Bernard Tomic, Australia, def. Jozef Kovalik, Slovakia, 7-6 (5), 6-4, 6-4
Sam Groth and John Peers, Australia, beat Andrej Martin and Igor Zelenay, Slovakia, 6-4, 6-2, 6-7 (3), 7-6 (2).
Canada 2, Chile 0
Frank Dancevic, Canada, beat Christian Garin, Chile, 6-3, 6-7 (5), 6-1, 6-4.
Vasek Pospisil, Canada, beat Nicolas Jarry, Chile, 6-1, 5-7, 7-6 (2), 6-3.
Russia 1, Kazakhstan 0
Andrey Kuznetsov, Russia, beat Aleksandr Nedovyesov, Kazakhstan, 6-3, 6-4, 5-7, 7-5.
Spain 3, India 0
Feliciano Lopez, Spain, beat Ramkumar Ramanathan, India, 6-4, 6-4, 3-6, 6-1.
David Ferrer, Spain, beat Saketh Myneni, India, 6-1, 6-2, 6-1.
Marc Lopez and Rafael Nadal, Spain, beat Saketh Myneni and Leander Paes, India, 4-6, 7-6 (2), 6-4, 6-4.
Germany 2, Poland 1
Jan-Lennard Struff, Germany, beat Kamil Majchrzak, Poland, 6-7 (8), 6-3, 5-7, 6-2, 6-1.
Florian Mayer, Germany, beat Hubert Hurkacz, Poland, 1-6, 7-6 (6), 6-4, 7-5.
Lukasz Kubot and Marcin Matkowski, Poland, beat Daniel Brands and Daniel Masur, Germany, 6-7 (5), 4-6, 6-3, 6-4, 6-2.
Japan 3, Ukraine 0
Taro Daniel, Japan, beat Sergiy Stakhovsky, Ukraine, 7-6 (4), 7-6 (2), 6-1.
Yoshihito Nishioka, Japan, beat Illya Marchenko, Ukraine, 6-4, 5-7, 6-4, 7-5.
Kei Nishikori and Yuichi Sugita, Japan, beat Artem Smirnov and Sergiy Stakhovsky, Ukraine, 6-3, 6-0, 6-3.
With inputs from agencies