Kei Nishikori’s historic run at the Australian Open generated a torrent of publicity for his sponsor, Fast Retailing Co., but Sony Corp. and Adidas AG both missed out after declining to renew endorsement deals with Japan’s top tennis player.

NHK purchased the rights to air Nishikori’s Australian Open quarterfinals match Wednesday against British No. 4 seed Andy Murray, which an estimated 55 million viewers tuned into.

The 22-year-old became the first Japanese player in 80 years to reach the $12 million tournament’s final eight, and is the highest-ranked Japanese men’s tennis player on record.

Nishikori ultimately lost the match against Murray, but “the marketing effect of this endorsement is worth tens of billions of yen,” said Toshihiro Nagahama, chief economist at Dai-ichi Life Insurance Research Institute.

Fast Retailing, which last week cut its annual sales growth forecast to 0.7 percent, has said the company benefits from its relationship with Nishikori even though it has resisted calls to market a tennis line based on him. Uniqlo is getting “a lot of requests, more than ever” from consumers seeking to buy the shirts, shorts and hats that Nishikori wears on court, said Masahide Sakamoto, a Uniqlo adviser who travels with the player to tournaments.

“The fact that their phones are ringing is exactly why Kei is doing endorsement deals that are much larger than for the average tennis player,” said Olivier van Lindonk, Nishikori’s agent and tennis vice president at IMG Worldwide Inc. He said the Uniqlo endorsement proposal was “more aggressive” than Adidas’s, but declined to disclose how much the deal is worth.

Adidas Japan spokesman Yoshitaka Ikeuchi was not available for immediate comment.

Nishikori, the son of a piano teacher and an engineer in Shimane Prefecture, started playing tennis at age 5, and at 14 was selected to train at the IMG Bollettieri Academy in Florida thanks to a sponsorship deal with the Masaaki Morita Tennis Fund, established by Sony Life Insurance Co.’s former CEO.

After recovering from elbow surgery in 2009, Nishikori regained his place among the world’s top 100 players the following year and ended 2011 ranked 25th. Last year was also notable for his defeat of world No. 1 Novak Djokovic in December.

“The ripple effects for sponsors when athletes do well are huge,” said Nagahama of Dai-ichi Life.

Sony helped Nishikori at the start of his career but isn’t getting the full “ripple” now that he has become one of the world’s leading players, he said.

The consumer electronics maker, which has said it intends to cut costs after posting a third straight annual loss last fiscal year, let an endorsement deal with Nishikori expire Nov. 13.

Adidas, which has endorsements with tennis players including Murray and Frenchman Jo-Wilfried Tsonga, the No. 6 seed Nishikori defeated on his way to the quarterfinals in Australia, lost out to Uniqlo last year over Nishikori’s clothing deal. Nishikori and IMG chose Uniqlo partly because it offered “greater long-term potential for Kei to earn money,” van Lindonk said.