Big-serving Sam Groth has become the latest Australian casualty on a horror day for the local men at the Brisbane International.
The reigning Newcombe Medallist was beaten by South Korean teenager Hyeon Chung 7-6 (10-8) 6-4 in the first round at Pat Rafter Arena on Monday night.
World No.51 Chung booked a second-round clash with third seed Marin Cilic.
Earlier Aussie wildcards Ben Mitchell and John-Patrick Smith also fell at the first hurdle.
The remaining Aussie men – Bernard Tomic, wildcard James Duckworth and qualifier Oliver Anderson – feature in first round action on Tuesday.
Davis Cup regular Groth, appeared in complete control against the bespectacled 19-year-old when he led the first set 5-2.
But Chung showed why he was voted last year’s ATP most improved player by finding a way to blunt Groth’s serve that pushed 230kph.
World No.60 Groth made 26 unforced errors as his first set unravelled.
He came back from 4-1 down in the second but Chung closed out the match against the shellshocked local.
Groth had been expected to at least match his 2015 Brisbane performance when he downed defending champion Lleyton Hewitt on the way to the quarterfinals.
The 28-year-old – holder of the world record for the fastest serve at 263kph – went on to have a breakthrough 2015.
He received the Newcombe Medal after helping Australia reach the Davis Cup semi-finals and reached the third round of a major for the first time at the Australian Open and then again at Wimbledon.
Earlier, German qualifier Tobias Kamke booked a second round clash with defending champion Roger Federer by downing local favourite Mitchell 6-2 6-4.
And Smith fell 4-6 6-3 6-2 to American Denis Kudla.
Meanwhile, Bulgaria’s Grigor Dimitrov upset fifth-seeded Frenchman Gilles Simon in the first round.
The 2014 Australian Open quarter-finalist, whose pop star girlfriend Nicole Scherzinger watched from the stands, will next meet the winner between American Steve Johnson and Serbia’s Viktor Troicki.