"It was a very tough match, she was playing really good and very aggressive," Doi told press after the win. "After the second set, I just tried to believe in myself and that I could do it, and just focused my tennis."
The No.41-ranked Japanese, who reached the final here last year, started out strong against Hibino, breaking twice to ease through the opening set. But Hibino, ranked No.102, hit back in the second - breaking twice and saving two break chances to restore parity.
"When he came to the court my coach told me to be more aggressive and add more spin, because [Hibino] likes to play with a flat ball," Doi explained. "I tried to move her around a lot, too."
In the third set, Doi saw her 2-0 lead erased as Hibino climbed back to level the match at 4-4. The pair wrestled for momentum until Doi finally broke for a third time to close out the two-hour battle and move into the second round.
No.7 seeded American Shelby Rogers had a more straightforward road into round two, breezing past local wildcard Lee Ya-Hsuan in an hour and 15 minutes.
"Playing a local girl like Lee was pretty fun," Rogers enthused after the match. "She had a lot of fans out there, and she had a really great game. She's definitely got a lot of potential.
"The first round is never easy, especially with the crowd against you but I'm happy I got through it and being in the second round."
Lee thrilled the Taiwanese fans when she grabbed the first lead of the match with a well-earned break to the Rogers serve, but it was short-lived as the American broke straight back. From then it was all Rogers, who eased into the second round in straight sets, 6-3, 6-4.
Tunisian qualifier Ons Jabeur knocked out Nicole Gibbs in a three-set battle, 6-4, 4-6, 6-1, while Mandy Minella advanced after a 1-6, 7-6(2), 6-4 win over Jana Cepelova. Romania's Sorana Cirstea saw herself being forced to retire in her match due to a left wrist injury, sending Risa Ozaki through, 7-6(3), 3-2.