Coming off a double gold in her maiden senior World Cup in Mexico recently, the 16-year-old Manu clinched the individual gold medal after prevailing over Thailand's Kanyakorn Hirunphoem in a thrilling final of the women's 10m air pistol event.
India tasted success in the 10m air pistol men's event too with Gaurav Rana winning a silver medal while Anmol Jain grabbed the bronze.
Manu shot 235.9 to finish top of the podium, while Hirunphoem had to be contend with silver after scoring 234.9.
Chinese Kaiman Lu (214.2) completed the 10m air pistol podium by winning the bronze.
In the men's event, Rana finished with a score of 233.9 while Anmol totalled 215.1 behind the Chinese gold medallist Zhehao Wang's tally of a junior world record 242.5.
Another Indian shooter in Manu's event, Devanshi Rana, also qualified for the final and finished fourth with 195.3.
The trio of Manu, Rana and Mahima Agrawal also brought India on top of the team podium with, while Xiao, Lu and Li Xue won silver for China. Thailand's Hirunphoem, Luxciga Srinitivoravong and Warunyapha Kaewngoen took the team bronze.
In an impressive display in the final of men's 10m air pistol event, India's Arjun Singh Cheema (152.7), Anhad Jawanda (134.4) and Abhishek Arya 114.5) finished 6th, 7th and 8th respectively.
India's Cheema, Rana and Anmol also pocketed the team gold, beating Liu, Wang and Tang — who claimed silver for China — and Jawanda, Arya and Adarsh Singh who won bronze for India.
An exciting final characterised the 10m air pistol junior event as Manu prevailed over Hirunphoem (16) at the very last shot.
After leading the match by as much as 2.2 points, Manu fired six consecutive shots outside the 10th ring, suddenly finding herself one point behind Hirunphoem with only two shots left to fire.
There, the 9.6-9.8 combo signed by the Indian was enough to overtake her rival, who instead sealed her fate with a disappointing 7.9.
Manu - who won individual and mixed team gold in air pistol at this month's ISSF World Cup in Guadalajara - finished with the score of 235.9 points, while Hirunphoem — who previously wrote a new qualification world record with 576 points — took silver with 234.9.
Gaurav Rana and Wang remained within 2.3 points with six shots to go but the Chinese shooter's impressive showing thereafter with consecutive shots of 10.7 and 10.6 points put him in comfortable lead.
China second and third final participant concluded at the feet of the podium, as 19-year-old Tang Sihao and 20-year-old Liu Jinyao respectively took 4th and 5th place.
Tang scored 195.3 points — losing a tie-breaking shoot-off against Anmol at the 20th shot mark — and Liu finished with 173.2.
The podium in Manu's event was completed by China's Lu Kaiman, 41st at last year's ISSF Junior World Championship in Suhl, Germany and making her first Junior World Cup participation Sydney.
Placing just outside of the podium, Manu's teammate Devanshi Rana failed to put a medal on top of her first international competition. The 18-year-old debutant took the fourth place with 195.3 points.
A second Chinese finalist — 15-year-old Xiao Jiaruixuan, air pistol junior gold medallist at last year's Asian Championship in Wako City, Japan, finished in fifth with 173.2 points.
She was followed by Singapore's 15-year-old Shirlene Hew Yun Ting and Chinese Taipei's 19-year-old Chien Hsin-Yi, who respectively finished in sixth with 153.3 points and in seventh position with 133.5.
At the bottom of the table, Amanda Mak Sao Keng (17) finished eighth in her first international competition ever, scoring 112.9 points.
India were second in the standings with 11 medals, including five gold, while trailing China led with 13 podium finishes.