In his first foray into the men's singles main draw at Melbourne Park since 2017, the Australian qualifier was outgunned 6-2 3-6 6-2 6-2 by Frenchman Hugo Gaston.
Heavy rain and thunderstorms forced the pair off Court 3 for more than six hours as Jasika was threatening to turn the tide early in the second set.
Heavy rain wreaked havoc on the first day of the Australian Open at Melbourne Park. (Joel Carrett/AAP PHOTOS)
When play got under way after 6pm, the 27-year-old Victorian immediately broke the world No.81 to send the tennis-deprived home crowd into raptures and went on to claim the second set.
But as the match wore on Gaston acclimatised to Jasika's unconventional game, smashing 55 winners and 33 unforced errors to steamroll into the second round.
Jasika famously became the first player in 28 years to win both the US Open boys' singles and doubles titles in 2014, and two years later got to the second round of the Australian Open.
But his quest for senior Tour success was derailed late in 2018 when he was banned for two years after testing positive to cocaine.
He spent time working in a factory and in a bar, watching the careers of his peers progress, before winning his way back into the Open main draw through qualifying.Â
Gaston had lost his only previous clash with a local at Melbourne Park, falling to Chris O'Connell in the opening round in 2022.
He will meet the winner of Czech 24th seed Jiri Lehecka and Australian Li Tu in the second round.
Frenchman Hugo Gaston scored a four-set win over local hope Omar Jasika at the Australian Open. (James Ross/AAP PHOTOS)
Jasika and Tu were among the five Australians in action on day one in Melbourne, along with Adam Walton, Aleksandar Vukic and Daria Saville.
More than 30mm of rain was recorded at Melbourne Park on Sunday.
Action was able to continue under closed roofs on the three main show courts throughout the afternoon, but only six matches were completed before 6pm local time.
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