Nishikori helps Japan to 2-1 Davis Cup lead over Canada
Japan's Kei Nishikori (L) and Yasutaka Uchiyama (R) celebrate their victory against Canada's Frank Dancevic and Daniel Nestor during their men's doubles tennis match of the Davis Cup World Group First Round in Tokyo on February 1, 2014 - by Toru Yamanaka
Japan will now be expected to claim a quarter-final place for the first time since the 16-nation elite group format was introduced in 1981.
The decision to play world number 18 Nishikori instead of Yuichi Sugita proved an inspired one after both teams had tweaked their doubles line-ups before a ball had been hit in anger.
Nishikori and Yasutaka Uchiyama produced an electrifying 6-3, 7-6, 4-6, 6-4 display against Daniel Nestor and Frank Dancevic, winning in a shade over three hours to give Japan their first world group doubles victory under the current system.
Injury-hit Canada, already missing talisman Milos Raonic with an ankle strain, replaced the struggling Vasek Pospisil with Dancevic and never really found their groove, despite brief resistance in the third set.
Japan now look odds-on to advance to an April date against either Davis Cup holders the Czech Republic or the Netherlands, unless Canada can somehow halt the swashbuckling Nishikori in the first of Sunday's reverse singles.
"I just want to focus on taking care of business so there is no pressure on (Go) Soeda," Nishikori told reporters. "I only found out last night I was playing in the doubles. I don't practice doubles normally but I was confident we could win today."
Canadian team captain Martin Laurendeau's dejected tone suggested his hand had been forced and the switch had not been tactical with Pospisil still suffering from back trouble.
"It's been a difficult tie for us," said Laurendeau. "Our top two players picked up injuries at the same time (at the Australian Open) in Melbourne and they just ran out of time to be ready. It's not over. Frank has played some great tennis and can do it again."
However, realistically the chances of the 119th-ranked Dancevic toppling Nishikori on the Tokyo hard-court where he won the 2012 Japan Open title appear more than remote.
Nishikori provided the spark in Japan's historic doubles win, a superb backhand lob giving Japan the first set before ripping a backhand across court to take the second-set tiebreak 7-3.
Canada hit back in the third but two successive net cords led to a break for the Japanese at the start of the fourth set, and they closed out proceedings on their third match point when Nestor dumped a backhand return into the net.
Japan team captain Minoru Ueda admitted after the match he had been unsure of what doubles combination to select.
"To be honest I was wavering between several options but thought Nishikori, with his experience, and Uchiyama's energy would be the best pairing," he said. "This was a big match to win. It is the world group and on this stage you have to leave it all out there."
Nishikori, who pushed Rafael Nadal hard in a fourth-round loss at the Australian Open, swept past Peter Polansky 6-4, 6-4, 6-4 in Friday's opening singles, but Dancevic beat Soeda 6-4, 7-6, 6-1 to leave the tie finely balanced.
Japan hold a 5-0 record against Canada in Davis Cup competition, although the last win came on grass in Montreal in 1938.