Japan's number one Kei Nishikori has been forced to pull out of this week's Davis Cup quarter-final against holders the Czech Republic in Tokyo because of a groin injury.
The 24-year-old aggravated the troubled area while beating Roger Federer in Miami last week, prompting him to withdraw from his semi-final against Novak Djokovic.
Nishikori said on Wednesday he would not be fit to face the Czechs, dealing a crushing blow to Japan's hopes of a major upset with world number five Tomas Berdych choosing not to travel to the Far East and Jan Hajek's sidelining with a knee injury.
"It's such a disappointment," world number 18 Nishikori told reporters after MRI scans revealed the extent of the damage to the left side of his groin.
"With the home-court advantage I really wanted to play in Japan's first quarter-final, which I do think we had a chance of winning. But after talking with the doctors, the prognosis wasn't good so unfortunately I can't play."
Nishikori, whose heroics helped Japan past an injury-depleted Canada and into the last eight of the Davis Cup for the first time under the modern format in February, is set to be replaced by 21-year-old Taro Daniel, ranked 190.
Team coach Minoru Ueda tried to remain upbeat despite having his worst fears confirmed.
"Losing Kei has definitely hurt the team's chances but we have to keep believing we can win," he said. "I believe Taro has the potential to be a top 100 player. The other players have to step up now."
Nishikori, who has proved a tough nut to crack at the venue to be used at the 2020 Tokyo Olympics, will support his team-mates from the bench and has targeted a return to the ATP Tour in Barcelona later this month.
"I'll carry on with rehab and look to play again at the (April 21-27) Barcelona Open," he said. "After the Davis Cup tie I'll go back to the States and get the injury properly fixed."
Japan, making their first quarter-final appearance since the Davis Cup introduced the 16-nation world format in 1981, now start as huge underdogs against a Czech side who have won the title the past two years.
With Berdych opting out, the visitors are led by Radek Stepanek and Lukas Rosol - both ranked in the 40s, while Nishikori's absence puts even more pressure on Go Soeda as Japan's senior player.