Okuhara took around one hour to beat Saina 15-21, 21-15, 22-20.
After losing the first game, Okuhara bounced back in style and bagged the second and third games to enter the semi-final.
Fifth seed Saina failed to to match the pace of her opponent and got beaten in a marathon match.
With this result, India’s campaign in the Korea Open ended.
The Japanese shuttler will now face her compatriot and top seed Akane Yamaguchi on Saturday.
–IANS
gau/mr