Spain endure nightmare start
Spain's Davis Cup hopes are hanging by a thread after they slipped to a 2-0 deficit on the first day of their first-round clash with Germany in Frankfurt.
The five-time champions, who have won three of the past six titles, travelled to Germany without any of their four highest-ranked players and paid the price for the weakened line-up on Friday.
Philip Kohlschreiber kicked things off with a 6-2 6-4 6-2 victory over Roberto Bautista Agut before Florian Mayer clinched a narrow 7-6 (8-6) 7-6 (7-4) 1-6 5-7 6-3 win against Feliciano Lopez.
Spain must now win all three remaining rubbers to avoid heading into the World Group play-offs.
Elsewhere, Serbia are on the brink of elimination after Switzerland stars Roger Federer and Staniaslas Wawrinka put the visitors 2-0 up in Novi Sad.
Last year's finalists and the winners in 2010 felt the absence of Novak Djokovic as Federer and Wawrinka dispatched Ilija Bozoljac and Dusan Lajovic respectively in the singles rubbers on Friday.
Federer gave his country the lead as he breezed past Bozoljac 6-4 7-5 6-2 before Australian Open champion Wawrinka was made to work slightly harder for a 6-4 4-6 6-1 7-6 (9-7) win over Lajovic in the World Group first-round tie.
Switzerland need to win just one of the three remaining rubbers to set-up a quarter-final clash with Kazakhstan or Belgium, with the former looking the much more likely opponent after taking a 2-0 lead in Astana.
Mikhail Kukushkin put the hosts in front with a 6-4 6-7 (7-3) 6-2 6-3 win over Ruben Bemelmans, while Andrey Golubev battled to an epic 7-6 (11-9) 3-6 4-6 6-2 12-10 victory against David Goffin to double the advantage.
Two-time defending champions the Czech Republic are in a better position after Tomas Berdych defeated Igor Sijsling 6-3 6-3 6-0 to draw his country level at 1-1 with the Netherlands.
France also have a two-rubber lead against Australia after Richard Gasquet and Jo-Wilfried Tsgona defeated Nick Kyrgios and Lleyton Hewitt respectively.
Argentina and Italy are tied at 1-1 after Carlos Belocq defeated Andreas Seppi 4-6 6-0 6-2 6-1 and Juan Monaco was beaten 7-5 6-2 6-2 by Fabio Fognini.
Injury-hit Canada fought back to level up their World Group clash against hosts Japan in Tokyo and leave the tie on a knife edge.
Japanese No 1 Kei Nishikori dispatched Peter Polansky with a comfortable straight sets victory but Frank Dancevic restored parity for last year's semi-finalists thanks to an impressive win over Go Soeda.
Canada's talisman Milos Raonic, sidelined with a sore ankle, was on the sidelines cheering on 135th-ranked Polansky, but he proved no match for world No 18 Nishikori who swept to a 6-4 6-4 6-4 success.
However, the teams shared the spoils on day one when Dancevic, a 29-year-old veteran of 19 Davis Cup ties, defeated Soeda 6-4 7-6 6-1.