By Martyn Herman
MADRID (Reuters) - Serbia sealed their place in the Davis Cup quarter-finals in straightforward fashion but Britain survived another nailbiter before joining them in the last-eight on Thursday.
Nicolas Mahut and Pierre Hugues-Herbert claimed a consolation win for France in the doubles but last year's runners-up, along with 2018 champions Croatia, miss out.
Britain's Group E decider against Kazakhstan went to the wire with doubles duo Jamie Murray and Neal Skupski edging Leon Smith's side home for the second day running.
Former world number one Andy Murray was given a day off after his near three-hour win against Dutchman Tallon Griekspoor 24 hours earlier but his replacement Kyle Edmund beat Mikhail Kukushkin 6-3 6-3.
Bublik beat Dan Evans 5-7 6-4 6-1 to level the tie and raise hopes among the vociferous Kazakh fans but Murray and Skupski, cheered on by a large British fan club, easily beat Bublik and Kukushkin 6-1 6-4 to seal a 2-1 win.
Germany made sure of top spot in Group C as veteran Philipp Kohlschreiber beat Chile's Nicolas Jarry in the opening rubber of their tie on Thursday. A 2-1 win for the Germans meant they qualified in first place ahead of Argentina.
Argentina survived as one of the two best runners-up.
After 18 ties spread over three and a half hectic days at La Caja Magica, the quarter-final line-up is now complete.
Canada face Australia in Thursday's evening session with the other three quarter-finals -- Serbia v Russia, Spain v Argentina and Britain v Germany taking place on Friday.
While there have been plenty of teething problems for the inaugural version of the revamped Davis Cup, the knockout phase looks enticing as world number one Rafael Nadal bids to lead Spain to the title on home soil.
Djokovic, the man he knocked off the rankings top spot this month, also looks hungry to end his year on a high though.
The 32-year-old, who inspired his nation to the title in 2010, is now on a 14-match winning streak in Davis Cup singles.
"It was important just to win every match and we did that after singles," Djokovic told reporters. "I think both Filip and I are in very good form. There are a lot of quality teams here, but I think we have had a perfect score so far with winning all the sets and hopefully we can keep going."
Thursday's schedule went far more smoothly than the previous two days when play finished in the small hours, attracting criticism about the new Davis Cup format.
The previous night the U.S. and Italy contested what was effectively a dead doubles rubber until 4am.
"I heard about the 4am finish," Djokovic said. "I think it was always going to happen, knowing that you have 18 teams and you're trying to squeeze everything in one week."
The International Tennis Federation voted to change the format in 2018 in partnership with Spanish investment company Kosmos who have pledged $3 billion over 25 years.
The World Group, which featured home and away ties across the year before a November final, has now been replaced by an 18-nation showpiece in one city.
(Reporting by Martyn Herman; Editing by Toby Davis)