This was former world number one Osaka's second win from the five matches she has played since returning last month after a 15-month time out on maternity leave from the tour.
The Japanese four-time Grand Slam winner was exacting a small measure of revenge on Garcia with this 7-5, 6-4 success in Doha as it was the French star Garcia who knocked her out in the first round of last month's Australian Open.
And she reckons she is beginning to find her stride again after becoming a mum.
"I feel like I'm a much better player now. In Australia, my returns weren't as good and I don't feel like I was as focused as I am now," said the match-winner.
On coming back physically after pregnancy she added: "It’s been a really tough journey.
"I felt like I was chasing myself in the past and it honestly wasn't really healthy to do.
"After giving birth, I feel I trained really quickly, I’m a very big perfectionist and it's tough when you don't see results as quickly.
"I felt like I was driving a car that wasn't mine. So my body didn't feel like the body that I was used to."
"It was in that journey I felt like I learned how to love myself as I am now. I got to wake up every day and see my daughter and know that I was strong enough for her to come into this world."
Osaka's next assignment on her comeback trail is a second-round date with Petra Martic of Croatia.
This is the second time the pair have crossed swords but it comes a decade after their first encounter.
A 16-year-old Osaka prevailed on that occasion, a final qualifying round match at Stanford in 2014.
The omens did not look great for Osaka on Monday as Garcia won her first 11 service points but she knuckled down and finally broke the Spaniard when she was serving for the set to level at 5-5.
She then fended off two break points before wrapping up the set with a love break.
A further break of serve in the last game of the match earned her the pick-me-up win she needed after her early knockout a week ago.
"Every time I had a break point opportunity, I was very accurate on my shot," said Garcia.
"And I was able to take this opportunity in Australia and today I was not.
"The same as Australia, it was played on very few points alone. Those points she was a better player today."
