The top seed Saina dropped a game after having an advantage but with Nozomi retiring early on in the third game, the Indian cemented her place in the last four stage of the tournament with a 21-11 14-21 2-0 win in a 43-minute contest.
She will next take on sixth seed Tzu Ying Tai of Chinese Taipei tomorrow.
Saina dominated the proceedings early on. Having opened up a 3-0 lead, she not only maintained it but also slowly and steadily widened the gap to take a 1-0 lead in the match.
The Hyderabadi girl was immaculate with her placements as she made her opponent run around the court and caught her at the forecourt a few times.
A few of her strokes went wayward and she was a little rusty at the nets too. However, that didn't stop her from pocketing the first game when Nozomi's long shot went out.
The match was disrupted for about five minutes after the first game due to a technical problem, which led to lack of lights on the court.
After resumption of the second game, Nozomi got her act together and started playing a fast paced game. Saina tried to respond but she committed few unforced errors and also her strokes were not accurate, even as her opponent moved into the breather 11-2.
Saina tried to narrow the gap after the breather but it was too much of a gulf to bridge and the Japanese roared back into the contest with the Indian hitting wide.
During the break, Nozomi was seen wrapping up her knees but once the decider started she had difficulty in moving. At 0-2, Nozomi decided to throw in the towel after she broke down on court while playing a back court return.
Asked what led to her the Japanese's retirement, Saina told PTI: "It is because of a slight knee problem, I think."
