But unfortunately for the Niagara Falls, Ont., native, a pulled muscle wouldn't allow him to go past the second set.
Japan sealed its victory over Canada in the first-round Davis Cup tie after Nishikori downed an ailing Dancevic 6-2, 1-0. Later Sunday, Peter Polansky of Thornhill, Ont., lost to Go Soeda in the fifth match 6-1, 6-4 to increase Japan's margin to 4-1.
"Kei came out playing really well today and once I pulled a stomach muscle early in the second set there was no way I could stay with him when I could only serve at 20 per cent..." Dancevic said.
"Under other circumstances I probably wouldn't have even stepped on the court with the way I was feeling, but this is Davis Cup and I wanted to give it all I had and push to the limit because this situation means a lot to me."
Dancevic, ranked 119th in men's singles, held his serve during the first game, but World No. 18 Nishikori went on to break twice and win the next five games to eventually take the set.
After being broken to start the second set, Dancevic took a medical timeout and was forced to retire, handing the match and the tie to Japan.
Canada will play a World Group playoff in September in hopes of keeping its spot in the upper echelon of the competition. Japan, meanwhile, will face the winner of a tie between the Czech Republic and the Netherlands in the Davis Cup quarter-finals.
The Canadian squad was missing its top two singles players at the tournament as both No. 11 Milos Raonic of Thornhill, Ont., and No. 25 Vasek Pospisil of Vancouver were unable to recover from injuries in time to play. Polansky, who lost Canada's first singles match to Nishikori on Friday, replaced Raonic.
Dancevic stepped in for Pospisil in the doubles match with Daniel Nestor on Saturday. The Canadian duo, who hadn't played together in three years, lost to Nishikori and Yasutaka Uchiyama 6-3, 7-6 (3), 4-6, 6-4.
"We just battled with so many things this week and nothing really went our way when it came to injuries," said Canadian team captain Martin Laurendeau. "It's obviously disappointing but you can't blame these guys. They gave their all.
"... Frank and Peter stepped in and left everything on the court every time they went out there. With what we accomplished last year (reaching the semifinal) we didn't want to take a step back like this but hopefully everyone gets healthy and has a strong season and we can fight hard to keep our spot in September."