Queensland's last man standing, who'd enjoyed a hair-raising ride through Paris qualifying, found Britain's new big hope Cameron Norrie a barrier too far as he was squeezed out 6-3 6-4 6-3 in Wednesday's second-round clash.
It meant that for the fifth time in six years, no Aussie man has been able to get beyond the last-64, leaving only Daria Saville and Ajla Tomljanovic to fly the flag for the women later on Wednesday.
Not that Kubler needed to berate himself, as the world No.160 acquitted himself admirably in just his third-ever grand slam main-draw contest against the rising Norrie, 11th-ranked in the world, 10th seed here and twice a tournament winner already this season.
The second of Kubler's slam wins had come in a late night thriller against American Denis Kudla under lights on Sunday, which had left him emotionally and physically drained.
It was the highlight of an unexpectedly long stay at the tournament for Brisbane's former world junior No.1, who had twice come close to being knocked out during the qualifying rounds, saving a match point in his second match last week.
But Norrie, a consistent left-hander who drains opponents by making them work for every point, was always going to be a fiendishly difficult follow-up.
Though Kubler maintained his aggressive approach throughout and was competitive in the final two sets, actually leading 3-0 in the third, the Briton wore him down inexorably to triumph in just under two-and-a-half hours with his effective form of tennis strangulation.
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