Top seed Stefanos Tsitsipas lost in straight sets in the Queen's quarter-finals to Canadian teenager Felix Auger-Aliassime.
Tsitsipas, 20, lost 7-5 6-2 to the 18-year-old eighth seed.
Auger-Aliassime, the youngest Queen's semi-finalist since Lleyton Hewitt in 1999, beat Grigor Dimitrov and Nick Kyrgios in the first two rounds.
"I had zero expectations coming here. I had three matches against amazing players but held my nerve," he said.
"We'll see how far I can go here and at Wimbledon."
The Canadian, who made his only Grand Slam main draw appearance at the 2018 US Open, will play Andy Murray's doubles partner Feliciano Lopez in the semi-finals.