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.

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.