Australia's singles hopes in the Dubai Tennis Championships have all departed after Chris O'Connell's bold challenge against No.3 seed Hubert Hurkacz fell short.
Alexei Popyrin, who had made the last-four of the previous week's Qatar Open in Doha, had to pull out of the tournament with an abdominal strain, leaving all the onus on his fellow Sydneysider, 29-year-old O'Connell, in Wednesday's round-of-16 ties.
And though O'Connell served well to keep Hurkacz honest for most of the match, just a couple of cheap errors at the end of a tight first-set tiebreak and one loose service game in the second stanza was enough for Poland's world No.8 to advance 7-6 (7-5) 6-4 after just over an hour-and-a-half.
Seeking to reach his second quarter-final of the year after the Adelaide International, O'Connell could not be faulted for going on the attack against Hurkacz, and did well to drag the Pole into yet another tiebreak without even offering up a break-point chance.
O'Connell was continuing the form of his opening-round win against German qualifier Maximilian Marterer, when he went unbroken throughout.
Hurkacz has been getting fed up of being dragged into breakers - this, remarkably, was his ninth consecutive set to be decided by one.
He came out on top after a wild O'Connell forehand found the tramlines - a 16th unforced error off that wing from the Australian, who was still gambling on attack.
Hurkacz finally found a way of breaking through in the second set by standing further back to return serve, which seemed to unsettle O'Connell as he succumbed to the only break of the match in the seventh game.
Second seed Andrey Rublev dismantled French qualifier Arthur Cazaux 6-4 6-4 to reach the quarter-finals for the fifth straight year, and will next play American Sebastian Korda, a 6-1 6-0 winner over Botic van de Zandschulp.
Ugo Humbert outplayed Andy Murray 6-2 6-4, with the former world No.1 confirming afterwards this may well be his final year in tennis.
Top seed Daniil Medvedev recovered from a set down to beat Lorenzo Sonego 3-6 6-3 6-3 for a place in the last eight.
Medvedev, the reigning champion in Dubai, on Tuesday played his first match since losing the Australian Open final to Jannik Sinner, beating Kazakhstan's Alexander Shevchenko 6-3 7-5.
He will next face eighth-seeded Alejandro Davidovich Fokina of Spain.
The remaining Australian interest is 36-year-old Matt Ebden, the new world doubles No.1, who will feature alongside Rohan Bopanna in Thursday's quarter-final against Uruguay's Ariel Behar and Czech Adam Pavlasek.
Ebden celebrated his landmark when he and 43-year-old Bopanna scraped past Skander Mansouri, of Tunisia, and Pakistan's Aisam-ul-Haq Qureshi 7-6 (7-4) 7-6 (7-5) in the opening round.
