Roger Federer was defeated at the hands of Grigor Dimitrov in the quarterfinals of the US Open at Arthur Ashe Stadium.
The 20-time Grand Slam winner had looked destined for a box-office final against Rafael Nadal.
Dimitrov beat Federer, who needed a medical time-out and looked out of sorts throughout a five-set defeat, hitting 60 unforced errors.
Dimitrov had not beaten Federer in any of their previous seven matches and had taken only two sets off him.
“I just feel low,” Federer said. “Just disappointed it’s over because I did feel like I was actually playing really well after a couple of rocky starts.
“It’s just a missed opportunity to some extent that you’re in the lead, you can get through, you have two days off after. It was looking good.”
Dimitrov is the lowest-ranked US Open semi-finalist in 28 years, and he managed to overcome his nerves ahead of the match to come out on top.
He said: “It’s been a while since I’ve been on this court so I was nervous in the first set and he served really well.
“I think after the second set I felt I was getting a good stride on my shots.
“We had a really long game in the fourth set and I wanted to make him stay on court for long as possible.
“For sure he was not at his best at the end. It’s the best of five and anything can happen.”
In the last four, the Bulgarian will face Daniil Medvedev, who knocked out Stan Wawrinka to reach his first Grand Slam semi.