Former world number one Roger Federer, 35, who lifted his 18th Grand Slam title at the Australian Open in January, had match points in the second-set tiebreak and also led 5-1 in the third-set breaker.
Evgeny Donskoy and Konstantin Kravchuk battled back from a set down twice winning 4-6, 7-6 (7/3), 5-7, 7-5, 6-4 in four hours five minutes to keep their team's slim chances to advance into the Wold Group play-offs alive.
Andy Murray, the reigning Olympic and Wimbledon champion, will next face Uzbekistan's world number 65 Denis Istomin, who put out Italian 20th seed Andreas Seppi, 6-3, 6-4, 2-6, 3-6, 6-1.
Fish will take on Jarkko Nieminen of Finland in the second round of men's final tuneup event before the U.S. Open
Marathon man John Isner finished a quick Grand Slam match for a change, beating 66th-ranked Evgeny Donskoy of Russia 6-1, 7-6 (5), 7-6 (2) Monday in the first round of Wimbledon.
Devvarman, ranked 254, lost the first set to Donskoy, who is ranked 78, by 4-6. The Indian then fought his way back in the second set to take it in a thrilling tie-breaker. With Donskoy rattled, Somdev took control in the deciding set and cruised past 6-2 to seal the match.
The 22-year-old Russian displayed a varied array of shots and had Murray in a 5-1 hole after just 24 minutes. The Scot reeled off four straight games to knot the set. But he was unable to convert any of six break chances in the 11th game.
Nishikori completed a 7-6 (7/3), 6-2, 6-3 victory in 2hr 6min on Show Court Two to get to the last 16.