The Australian world number six is regarded as one of the best exponents of grass court tennis, but was unable to handle the aggressive Nakashima in a 7-5, 6-3 quarter-final defeat.
A tight opening set dominated by serve was edged by world number 32 Nakashima as he converted the first break point of the match in the 12th game.
De Minaur had a chance at 1-1 in the second set on Nakashima’s serve but was unable to take it.
On a boiling hot day on Andy Murray Arena, he dropped serve at 3-4 , and there was no way back as Nakashima clinched his first win against a top-10 player in two years.
Nakashima will face Argentina’s seventh seed Francisco Cerundolo after he battled past British wildcard Arthur Fery 7-6(1) 3-6 6-4. Cerundolo suffered a scare when he was struck in the throat by a Fery backhand from close range and was left on the ground.
“I got hit and I couldn’t breathe, but after one or two games it went away,” he said.
The other semi-final will see American former champion Tommy Paul take on France’s Ugo Humbert. Paul beat fourth seed Alejandro Davidovich Fokina of Spain 6-3, 7-6(4) while Humbert thrashed Australia’s Rinky Hijikata.
