American duo Taylor Fritz and Reilly Opelka crashed out of the inaugural Adelaide International at the first hurdle on Sunday.
Fifth seed Fritz was always on the back foot against Kazakhstan's Alexander Bublik as he lost 6-4 7-6 (7/4) despite saving three match points in the second set.
It was a third defeat from four outings in 2020 for Fritz, ranked 31st, after disappointment at the ATP Cup last week.
Opelka squandered his chance to advance as he missed three match points in the second set of a 5-7 7-6 (11/9) 7-6 (7/2) defeat to Uruguay's Pablo Cuevas.
Home hope Alexei Popyrin entered the tournament as a wildcard but could not get past Serbia's Laslo Djere in their first-round encounter, losing 7-6 (7/3) 3-6 6-4.
