The fifth-seeded Saina, who was expected to win at the event given the absence of some top Chinese players, lost 21-11, 22-20 to her little-known Japanese rival.
The match was contested evenly to start with but Hirose, who was a semifinalist at the event once before as well, took control by breaking through the rallies that Saina generally wraps up in her favour.
Saina came back in the second game and it went neck and neck but the Indian ultimately fell short as Hirose held her nerves to clinch the issue.
With Saina’s loss, India’s campaign at the event ended as all her compatriots had already crashed out in previous rounds.
Dan halts Zwiebler
Four-times winner Lin Dan of China ended the brave run of Germany's Marc Zwiebler with a 21-9, 16-21, 21-11 victory in the semifinals on Saturday.
Zwiebler's victims on his march to the last four included world champion Chen Jin but Olympic gold medallist Lin proved a bridge too far.
The Chinese was at his best in the first game with a classic mix of power and guile but the German fought back bravely in the second only for Lin to regain control early in the decider and go on to clinch a place in the final for a seventh time.
Zwiebler, 27 on Sunday, was generous in defeat, telling reporters after his career-best run: "It's been a very great week for me. No excuses. He was the better player today but maybe next time I can win another game or two."
The German then headed for the airport to fly out for a holiday in Italy, twice postponed this week as he progressed in the tournament further than he had ever anticipated.
Meanwhile in the quarterfinals on Friday, World number one and defending champion Lee Chong Wei of Malaysia defeated eighth seed Boonsak Ponsana of Thailand 21-15, 21-7 while fourth seed Peter Gade of Denmar lost to Chinese fifth seed Chen Long 21-12, 21-12.