The Swiss world No. 19, who has not competed since the Australian Open following the birth of his daughter, beat the 40th-ranked Spaniard 3-6, 6-4, 3-6, 7-5, 6-3 in the opening rubber of a tie missing superstars Roger Federer and Rafael Nadal.
Almagro began to show signs of fatigue by the fifth set, in which he made 15 unforced errors to Wawrinka’s five as well as three double faults.
The 24-year-old Spaniard, making his first Davis Cup appearance in two years, admitted it was a “tough match.”
In Bree, Belgium, last December’s losing finalist to Spain, the Czech Republic, took a 2-0 lead over outclassed Belgium as Tomas Berdych hammered Olivier Rochus 6-3, 6-0, 6-4 and Radek Stepanek defeated Xavier Malisse 6-2, 6-4, 7-6 (7-3).
It went 2-0 to France in Toulouse over Germany thanks to a one-two punch from Gael Monfils and Jo-Wilfried Tsonga.
Monfils dispatched German Philipp Kohlschreiber 6-1, 6-4, 7-6 (7-5) but it took Tsonga almost three hours to get past Benjamin Becker 6-3, 6-2, 6-7 (2-7), 6-3.
In Stockholm, world No.7 Robin Soderling overcame a mid-match wobble to beat Eduardo Schwank 6-1, 7-6, 7-5 on Friday and give Sweden a 1-0 lead in their Davis Cup first-round tie against Argentina.
Relying on a booming serve and powerful groundstrokes, Soderling downed his 64th-ranked opponent in two hours and 30 minutes, blasting 17 aces and 59 winners.
Last year’s French Open runner-up played a near flawless first set, dominating from the baseline and never facing a break point.
But the tenacious Argentine fought back in the second set as he started to read Soderling’s serve.
In Moscow, India were outclassed by two-time champions Russia on the opening day of their Davis Cup World Group first round clash on Friday.
Igor Kunitsyn battled from a set down to clinch a 6-7 (6/8), 7-6 (7/4), 6-3, 6-4 win in three hours 35 minutes over Somdev Devvarman, recording his third win over the 25-year-old Indian in as many meetings.
Mikhail Youzhny, currently 13th in the world, then won 6-4, 6-2, 6-3 in just one hour 43 minutes against Rohan Bopanna on the hardcourts of Moscow’s Luzhniki Small Sports arena.
In Melbourne, teenager Bernard Tomic led Australia to a commanding 2-0 lead over Taiwan in their Asia/Oceania Group I Davis Cup tie here on Friday.
Tomic, at 17 Australia’s youngest Davis Cup player in 77 years, crushed Taiwan’s Yang Tsung-hua, 6-2, 6-1, 6-1 in the opening singles rubber.
Australia’s nominated number one player Peter Luczak built on Tomic’s winning start to down Yi Chu-huan, 4-6, 6-3, 6-2, 6-3 and put the hosts 2-0 up heading into Saturday’s pivotal doubles.
In Osaka, Japan’s top player Tatsuma Ito struggled through to a five-set win to help his side take a 2-0 lead over the Philippines in the Davis Cup Asia-Oceania zone Group One tie on Friday.
Ito needed three hours and 13 minutes to score a 3-6, 6-3, 6-4, 3-6, 6-4 win over 698th-ranked Treat Conrad Huey in the opener of the best-of-five match contest on the artificial indoor court.
Ito is currently the country’s top player after Kei Nishikori’s ranking dropped to 898th this week because of a right elbow injury that has forced him out of action for almost a year.
Japan’s number-two Go Soeda dropped the first-set tie-breaker and the opening service game of the second set before storming back to beat Cecil Mamitt 6-7 (4/7), 6-3, 6-3, 6-3 without facing a single break point afterwards.
