Shi Yuqi overcame a stiff challenge from Lee Cheuk Yiu of Hong Kong to clinch his second India Open badminton title on Sunday.
The 27-year-old Chinese player, ranked second in the world, battled for 54 minutes to win the final 23-21, 21-17 and add to his 2018 title in New Delhi.
Shi, who was appearing in his second final in two weeks after a runners-up finish in Malaysia, remained on top of his baseline play and smashes against his relentless opponent.
After a hard-fought first game, Shi was tested again in the second when Lee took 10 straight points after trailing 6-14 but the Chinese kept his nerve to emerge the winner.
"In the second game, despite several contentious calls, Lee Cheuk Yiu went ahead. But I was patient and ultimately came through to win," said Shi.
"This victory is immensely significant in my career, given the prestigious nature of this tournament.
"Even though Viktor (Axelsen) is currently world number one, it is so competitive that anyone can claim the throne."
In the women's singles, Taiwanese Tai Tzu Ying served past reigning Olympic champion Chen Yu Fei of China 21-16, 21-12 in 42 minutes.
Chen, who beat Tai in the Olympic final in Tokyo, raced to 7-1 before her opponent hit back with aggressive play and soon took the lead as a raucous crowd cheered on.
Chen stretched the opening game with some fighting rallies but Tai came roaring back in the second to make a huge statement in the build-up to the Paris Olympics.
"I was feeling a bit nervous but I got a lot of support from the fans," Tai said.
"I will fight for the medal in this year's Olympics. I know it's going to be difficult but I am working hard for it."
Japan's Mayu Matsumoto and Wakana Nagahara were crowned women's doubles champions after they beat Zhang Shu Xian and Zheng Yu of China 21-12, 21-13.
Thailand's Dechapol Puavaranukroh and Sapsiree Taerattanachai clinched the mixed doubles title with a 21-16, 21-16 win over Jiang Zhen Bang and Wei Ya Xin of China.
It was heartbreak for the Indian fans after local heroes Satwiksairaj Rankireddy and Chirag Shetty went down in a thrilling men's double final won by the South Korean world champions Kang Min-hyuk and Seo Seung-jae 15-21, 21-11, 21-18.