Osaka, a two-time champion in Melbourne, was competing in her first grand slam tournament in more than a year when she fell to Garcia 6-4 7-6(7-2) on Monday.
The Japanese star took 15 months away from tennis to prioritize her mental health before becoming a mother for the first time in July.
She battled hard in a tight match against the 16th-seeded Garcia on Rod Laver Arena but trailed in the first set when the Frenchwoman secured a break of serve at 2-2 – the only break of the match.
A close second set was decided by a tie-break, during which Garcia pulled clear and wrapped up the contest when Osaka’s cross-court backhand struck the net.
“For me, I felt like I did the best that I could possibly do,” Osaka told reporters after the match. “It was just really nice to be on Rod Laver again, hear the audience, how much they interacted with the match.”
All the seeded players at the Australian Open would have been desperate to avoid Osaka in the first round after her ranking had dropped during her time away from the sport.
But the 30-year-old Garcia produced an assured performance against the four-time grand slam champion, hitting 13 aces – including two in the second-set tie-break – and 34 winners.
She will now face unseeded Polish player Magdalena Fręch in the second round.
Prior to the Australian Open, Osaka marked her return to tennis with a victory against Germany’s Tamara Korpatsch. She then lost to Czech star Karolína Plíšková in three sets in the second round at the Brisbane International tournament.
“I think I’ve learned a lot during this trip, both on the court and off the court,” said Osaka. “Also, I think I just played some really good people. It’s a little unfortunate … I think I just have to see how the rest of my season goes.”
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