A round-up of results from Davis Cup matches played on Sunday
Andy Murray won a gripping five-set match against Japan's Kei Nishikori to secure a 3-1 Davis Cup win for the champions and a quarter-final with Novak Djokovic's Serbia.
Murray, whose heroics helped clinch the title against Belgium last year, was pegged back after taking the first two sets, but eventually prevailed against the world number six 7-5, 7-6(6), 3-6, 4-6, 6-3 in four hours and 54 minutes.
It was Murray's first event back on court since the birth of his daughter, but any doubts over his fitness were dispelled as he once again carried Britain's hopes almost single-handedly, winning three matches, including the doubles, in three days.
"I am lost for words at this stage; he (Murray) is a man of steel, isn't he?" Britain's captain Leon Smith said.
"What Andy managed to do was astonishing since he hasn't played since the Australian Open final."
After his exertions, Murray said he was keen to get back to his family.
"It's (wife) Kim's first Mother's Day, so it will be nice to get to see her this evening. I'll try to get back for bath time and to put her to sleep -- the baby, not Kim."
Murray has been dogged by the shadow of Fred Perry for much of his career, but victory over Nishikori allowed him to put another Perry milestone behind him.
Having become the first British man since Perry to win a grand slam and then Wimbledon, Murray surpassed the former great by improving his unbeaten streak in Davis Cup singles and doubles rubbers to 14.
The win was the joint-longest match of Murray's career along with his 2012 US Open final triumph against Novak Djokovic, who he will now face in the quarter-finals in Serbia in July.
World number one Djokovic was also involved in an epic tussle on Sunday and took almost five hours to beat Mikhail Kukushkin in five sets.
That drew Serbia level at 2-2 against Kazakhstan before Viktor Troicki finished off the tie by beating Aleksandr Nedovyesov in the deciding rubber.
World No 1 Djokovic needed four hours and 57 minutes on Sunday to defeat Mikhail Kukushkin 6-7 (6-8), 7-6 (7-3), 4-6, 6-3, 6-2 to pull Serbia level at 2-2 with Kazakhstan in Belgrade.
Viktor Troicki then beat world number 200 Aleksandr Nedovyesov 6-2, 6-3, 6-4 to put 2010 champions Serbia into a July 15-17 quarter-final with defending champions Great Britain, which will see a super showdown between Djokovic and Murray.
Djokovic hit 19 aces and 37 winners but committed 94 unforced errors in his epic win over Kukushkin.
"This was one of the most difficult matches in my career both physically and mentally," said 28-year-old Djokovic, who again was feeling the effects of a shoulder twinge.
Croatia, the 2005 champions, needed a final rubber to defeat last year's runners-up Belgium in Liege when 19-year-old Borna Coric swept past Kimmer Coppejans 7-6 (7-5), 6-2, 6-2.
David Goffin had brought Belgium level at 2-2 by seeing off former US Open champion Marin Cilic 6-4, 6-4, 3-6, 7-5.
Italy, the 1976 champions, had already made sure of their last-eight place on Saturday against 2014 winners Switzerland, playing without Roger Federer and Stan Wawrinka, in Pesaro.
They completed a 5-0 rout on Sunday and will face Argentina for a semi-final spot.
Argentina, runners-up three times since 2006, beat World Group debutants Poland in Gdansk when Leonardo Mayer defeated Michal Przysiezny 6-7 (4-7), 7-6 (7-4), 6-2, 6-3 in the first of the reverse singles.
The remaining quarter-final will see France, who swamped Canada 5-0, take on 2012 and 2013 champions the Czech Republic, who defeated Germany 3-2 in Hanover.
Lukas Rosol sealed the deciding rubber, needing just 98 minutes to beat teenager Alexander Zverev 6-2, 6-3, 6-1.
Earlier, Philipp Kohlschreiber had levelled the tie after Tomas Berdych retired injured after losing the first two sets 6-3, 7-5.