Tommy Paul ended Jack Draper's seven-match winning run on grass on Friday to reach the semifinals at Queen's but fourth seed Taylor Fritz crashed out in straight sets.
British No 1 Draper secured the biggest win of his career when he ended the Queen's Club reign of Wimbledon champion Carlos Alcaraz on Thursday.
But the 22-year-old was outgunned by American fifth seed Paul in the last-eight tie in London, going down 6-3, 5-7, 6-4 in a match lasting a shade over two hours.
Draper battled back from a set down but he was broken to love midway through the decider as the match swung Paul's way.
Defeat ended Draper's winning streak after he lifted his first ATP title in Stuttgart last week.
"I played good tennis and I like the grass," said Paul, 27. "I knew today was going to be a battle.
"It is never easy against Jack. He has been playing such good tennis so I am really happy to get through that one."
Paul will face compatriot Sebastian Korda in Saturday's semifinal after the world number 23 recovered from the loss of the first set to beat Australian wild card Rinky Hijikata 6-7 (4/7), 6-3, 6-4.
Italy's Lorenzo Musetti continued his impressive grass-court season by ending the run of British wild card Billy Harris 6-3, 7-5 to reach his second consecutive semifinal on the surface.
Musetti, who advanced to the last four in Stuttgart last week, fired 20 winners and committed just six unforced errors.
He is chasing his third tour-level title and will next play Jordan Thompson after the Australian defeated fourth-seed American Taylor Fritz 6-4, 6-3.
Thompson, who did not face a break point against Fritz, arrived in London on a five-match losing streak.