Australia's challenge at the Japan Open has crumbled at the quarter-final stage after Alex de Minaur and Alexei Popyrin both succumbed to inspired opponents in Tokyo.
De Minaur's push to reach the end-of-season ATP Finals may well be over after he was outplayed by resurgent Russian Aslan Karatsev 6-3 6-2 at the Ariake Coliseum on Friday night.
Then afterwards on the same court, Popyrin must have been left kicking himself as he went down 7-5 2-6 7-5 to young surprise packet Shintaro Mochizuki, who was cheered to the rafters by an ecstatic home crowd.
The statistics told an anti-climactic tale for Popyrin, who's made such impressive strides this year and was looking to progress to another semi-final in his fourth last-eight appearance of the year.
He hit more winners than the 20-year-old Japanese (40-36), more aces (21-4), won more points (103-94), made fewer unforced errors (23-27) and had a superior percentage of first serves in (72%-60%).
Yet he still couldn't quite get the job done against the young wildcard who just kept digging himself out of trouble and raising his game with the help of his noisy fans.
Mochizuki, the Wimbledon junior champion four years ago, was ranked only 319 at the start of the year but his brilliant, battling run in Tokyo as he's won his first three tour-level matches will transport him into the top 200 next week
Popyrin looked as if he had weathered the storm of Mochizuki's spectacular opening set when he responded with a couple of breaks in the second to quieten the crowd.
And he seemed poised to take control of the final set, only to have break points repelled by the Japanese in the first game and also at 5-5 as he applied huge pressure to the youngster's delivery.
But with the pressure at its highest, Popyrin let a 40-15 lead slip in the next game and ended up hitting a forehand approach wide on his first match point to go down in two hours 22 minutes.
The Australian's only consolation in a defeat, which will have been hard one to take, is that he'll make the top-40 in the world for the first time next week.
Mochizuki, who described his win as "unbelievable", will next face Karatsev, who looks to be back on one of those really hot streaks which Melbourne first witnessed on his remarkable run from the qualifying rounds all the way through to the 2021 Australian Open semi-finals.
World No.13 de Minaur, in his 10th quarter-final of the year, just couldn't cope with the power and accuracy of the 50th-ranked Karatsev, who broke his serve times en route to a high-level victory in one hour 36 minutes.
In the other quarter-finals, Ben Shelton beat his US compatriot Tommy Paul 7-6 (7-4) 6-3 to set up another all-American clash in Saturday's semis with qualifier Marcos Giron, the world No.79 who continued his fine week with a 6-1 6-4 win over Canada's Felix Auger-Aliassime.
