At the Pan Am Centre in Markham, Naraoka was pushed all the way by China's Li Shifeng but eventually sealed a 21-11, 19-21, 21-17 victory in 85 minutes.

He will now take on the defending champion and top seed Kunlavut Vitidsam from Thailand for the gold, after the favourite won his semi-final against India's Lakshya Sen 20-22, 21-16, 21-13.

In the women's event the Youth Olympic Games champion Goh Jin Wei from Malaysia is a step closer to adding the world junior title to her list of 2018 accolades after she beat China's Wang Zhiyi 21-19, 21-13 to advance to the final.

She will face Denmark's Line Christophersen next, who beat another Chinese player Wei Yaxin in the last four 21-18, 23-21.

She is looking to become Denmark's first world junior women's singles champion.

In the match of the day between Naraoka and Shifeng it initially looked like the game would be over much faster, as the Japanese player quickly won the first game and then raced into a 19-13 lead in the second, meaning he was just two points from the win.

With his place in the final on the line Shifeng clawed his way back with eight straight points to take it to a decider.

Shifeng played the more aggressive badminton throughout the third, but Naraoka's strong defensive play was too good in the end.

In the mixed doubles Indonesia are guaranteed the gold with two of their pairs making the final.

Leo Rolly Carnando and Indah Cahva Sari Jamil beat China's Shang Yichen and Zhang Shuxian 21-13, 21-23, 21-19 in the semi-finals, while Rehan Naufal Kusharjanto and Siti Fadia Silva Ramadhanti beat South Korea's Wang Chan and Jeong Na Eun 21-18, 21-18.