Nick Kyrgios' red-hot form has been halted after going down in three sets to eighth seed Hubert Hurkacz in the quarter-finals of the Canadian Open on Friday.
Hurkacz ran away with victory, triumphing 7-6 (7-4) 6-7 (5-7) 6-1 in one hour and 46 minutes in Montreal.
Wimbledon finalist Kyrgios had come into the encounter fresh from winning 15 of his past 16 matches, including lifting the title at last week's Washington Open. Kyrgios' run had fueled expectations around him at the upcoming US Open.
"Nick has been playing some incredible tennis throughout the past weeks, so it is a pleasure playing against him," Hurkacz said post-match in his on-court interview.
"I started really well. Nick was maybe a little bit injured, which might have hurt his serve. With both of us serving so well, that few per cent can make the difference."
Kyrgios was quick on serve but the 25-year-old Pole eventually ground him down, prevailing in the third set aided by an early break.
That break came after Kyrgios gave up two double faults, leading to the Australian to complain to the umpire about his opponent's mid-match break for a change of clothes.
The Australian was unable to break Hurkacz's serve throughout the match, with the Pole edging the aces count 20-19, while he was also superior on return. Kyrgios had more winners (55-47), but more unforced errors (24-13).
Hurkacz, who will face fourth seed Casper Ruud in the semi-finals, is the only former Masters 1000 champion left in the draw.
Ruud cruised into the last four with a 6-1 6-2 victory over hometown hero Felix Auger-Aliassime who was brushed aside in one hour and 14 minutes.
The Norwegian's win marks his third ATP Masters 1000 semi-final of the season, with the Canadian plagued by 21 unforced errors compared to Ruud's eight.
Unseeded Briton Daniel Evans fought back from a lopsided opening set to knock off Tommy Paul 1-6 6-3 6-4.
Evans will face Spaniard Pablo Carreno Busta after he defeated Jack Draper 7-6 (7-4) 6-1 in just under two hours.