Written byRajdeep Saha
Federer also saw his dear friend Stan Wawrinka bite the dust.
However, Serena Williams marched on to book a semi-final berth.
Elina Svitolina also advanced.
Here are the key results from Day 9.
The in-form Svitolina won the match 6-4, 6-4.
Konta was forced into making errors and that saw her lose the crucial moments.
"I didn't play badly at all, I was doing a lot of bright things. She just made me play that extra ball, it's frustrating," said Konta.
Serena has staked a claim as the favorite now to win the US Open 2019.
She overcame China's Wang Qiang in straight sets.
She hit 25 winners as she eased to a 6-1, 6-0 win over the 18th seed Qiang.
"I knew I needed to come out and play well. I'm feeling good, had a really tough year and I'm still here," she said.
Five-time US Open champion Federer was stunned by Dimitrov in a five-set thriller.
Federer had enjoyed a healthy record against Dimitrov but this time the Bulgarian had other ideas.
He fought back to clinch the match 3-6, 6-4, 3-6, 6-4, 6-2.
"Clearly in the end he was not at his best. I used every opportunity I had,' said Dimitrov after his win.
He reached his first Grand Slam semi-final at the US Open.
Medvedev received painkillers and taping on his thigh in the first set.
He sealed the match 7-6 (8-6,) 6-3, 3-6, 6-1.
"For sure, I hope to be ready for the semis," Medvedev said.
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