Hijikata struck eight aces and 25 winners to see off wildcard Tristan Schoolkate 6-4 6-4 in just 79 minutes at Memorial Drive on Tuesday.
Despite the straight-sets result, Hijikata said he never really enjoyed facing a countryman, especially a higher-ranked one.
Schoolkate is ranked 97th in the world, 18 spots above Hijikata.
"Tristan's had one hell of a year and I'm super pumped to see him starting the year in the top 100 - I've got a bit of catching up (to do) this year," Hijikata said.
"It wasn't the best year for me so I really wanted kind of to start strong in 2026 and put my best foot forward
"So I feel like I've put in a lot of hard work and I'm glad that it's kind of paying off so far."
While Hijikata joined home hero Thanasi Kokkinakis in the second round, Australian wildcard James Duckworth crashed out with a 6-3 6-3 loss to eighth-seeded Czech Tomas Machac.Â
Kokkinakis remains in doubt for his second-round clash on Wednesday with Monaco''s fifth seed Valetin Vacherot after suffering yet another injury in his tenacious three-set victory over Sebastian Korda on Monday night.
The luckless 29-year-old carried a painful shoulder problem throughout the match.
Fellow Australian Aleksandar Vukic is up against seventh-seed and former Australian Open finalist Stefanos Tsitsipas in Tuesday night's featured match.
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