Adelaide - A pair of American seeds crashed to defeat on Sunday's opening day of the ATP-WTA Adelaide International, with Taylor Fritz and Reilly Opelka failing to live up to their billing.
Tournament number five Fritz saved three match points but ended up losing 6-4, 7-6 (7/4) to Kazakhstan's Alexander Bublik.
The 31st-ranked American is off to a poor start in 2020 after suffering his third defeat from four matches since beginning his season last week at the ATP Cup in Perth.
Compatriot Opelka, seeded eight, met a similar fate, failing to convert on three match points in the second set to ultimately go down to persistent Pablo Cuevas of Uruguay 5-7, 7-6 (11/9), 7-6 (7/2).
The 36th-ranked American, who complained about not being chosen for his country's ATP Cup side, was unable to capitalise on his 36 aces.
Cuevas, who lost three matches at the ATP Cup for Uruguay, got his season back on track by reaching the second round, saving three of four break points against Opelka.
Women's play at the new Australian Open tune-up event is due to start on Monday.
Third seed Petra Kvitova, a Brisbane International semi-finalist, was a late withdrawal, with three-time unseeded Grand Slam winner Angelique Kerber moving up to take the Czech's spot in the draw.
A lucky loser from qualifying will also be inserted.
Australians head both fields, with ATP Cup semi-finalist Alex De Minaur and world number one Ashleigh Barty taking their respective top seedings.
Fritz was on the back foot from the start at Memorial Drive against the 55th-ranked Bublik.
The Kazakh won the opening set with one break of serve and ran away to 5-0 in the second set tiebreaker before Fritz could get onto the scoreboard.
The American staved off the inevitable as he saved three match points before losing in 99 minutes with Bublik next playing the winner from Briton Dan Evans and Argentine Juan Ignacio Londero.
The Adelaide tournament serves as the last event prior to the start of the Australian Open on January 20.