The five-time champion, Roger Federer, has crashed out of the US Open after Bulgaria’s Grigor Dimitrov won a late-night thriller against the Swiss tennis legend.
Federer, 38, had won all seven of their previous meetings, but Dimitrov fought back to secure a 3-6 6-4 3-6 6-4 6-2 win in New York.
Federer needed treatment for a back injury in the latter stages, allowing unseeded Dimitrov to take the victory.
Third-seed Federer, who lost to Australian John Millman in the last 16 last year, has now been knocked out of the US Open by players ranked outside of the world’s top 50 for the second successive year.
Afterwards, the 20-time Grand Slam champion said he was struggling with the back problem throughout the match.
“I feel low. I’m disappointed it is over because I feel as I though I was playing well,” Federer said.
“It is a missed opportunity. I thought if I could get through I’d have two days off after.
“I felt it the whole time, but I was able to play.”
Dimitrov, 28, will play Russian fifth seed Daniil Medvedev in the last four.
The shock win of Dimitrov, world number 78, ensured there will be at least one first-time Grand Slam finalist on Sunday.