Andy Murray's hopes of a fourth Olympic medal are over after he and partner Joe Salisbury lost 6-4 6-7 (2/7) 10-7 to Marin Cilic and Ivan Dodig in the men's doubles quarter-finals in Tokyo.
Murray - bidding to become the first player to win four Olympic medals since the sport was re-introduced to the Games - had pulled out of the singles event to concentrate on his partnership with Salisbury and the pair looked on course for the last four when they took the first set against Croatia's Cilic and Dodig.
However, their opponents dominated a second-set tie-break to force the deciding Champions Tie-Break in the third set where Cilic and Dodig prevailed 10-7 to book their semi-final spot.
Britain's only remaining player left in singles competition was Liam Broady. The world No 143 had made a surprise run to the last 16 but he lost out to France's Jeremy Chardy following a 6-7 6-4 1-6 defeat.
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Murray and Salisbury had impressed on their way to the last eight, starting with victory over France's second seeds Nicholas Mahut and Pierre-Hugues Herbert and following up with a second straight-sets victory over Germany's Kevin Krawietz and Tim Puetz.
After winning the opener, an early break over Cilic paved the way for them to take the initiative in the second set, but the Croatians responded impressively, breaking the Murray serve and going to win the second set on a tie-break before bossing the first-to-10 Champions tie-break.
Croatia raced into an early advantage and looked to be cruising when they led 8-3, but a spirited British pair fought back bravely and won four of the next five points to close to within two. However, Cilic and Dodig hung on to grab the point they need to reach the last four and stay in the hunt for a medal.
After the match, the pair were desperately disappointed, with Murray - now 34 and inching his way back to regular top-level tennis - admitted it may have been his last Olympics.
"I don't know if I'll get the opportunity to play again," he said having won singles gold at London 2012 and Rio 2016 to go with his mixed doubles silver alongside Laura Robson in 2012
"I've loved every minute of playing in the Olympics. I wish that today could have gone differently.
"I had another chance with Joe to win a medal, we were so close, and that's what's disappointing. I would like to have done some stuff differently in the match to try to help out more.
"I'll see how the injury heals. That's what will dictate it. I'm not going to rush something if it's not there.
"My team think I should be OK to play the US Open, judging by how I felt in matches here. It's not as physical as singles but there's a lot of explosive movements and my leg felt fine."
Murray still sounded disconsolate when he took to Twitter several hours later, writing: "I feel crushed after today's loss. Sport can be brutal.
"Thanks so much to Joe Salisbury for the opportunity to play. You were brilliant. I wish it could have gone a little better.
"If this is the end of my Olympics journey, I want to say a huge thanks to Team GB and all the tennis support team for everything they have done to help me perform at my best over the years.
"It's been an absolute privilege to represent you and my country at four Olympics and it's given me some of the best memories of my life."