The Thai sixth seed stunned top seed Carolina Marin of Spain in the women’s singles final 11-21, 21-16, 21-18 in one hour and 17 minutes at Vall d’Hebron Olympic Sports Centre.
It looked to be an easy workout for world No.8 Marin after the Spaniard cruised through in the opening game in just 15 minutes but Pornpawee bounced back in the second and pushed the match to the decisive third game.
Marin got off to a strong start and took early control but Pornpawee again clawed her way back to seal the match in front of a stunned home crowd.
Pornpawee received $12,750 winner’s cheque for her first title of the year, while Marin took home $6,460.
Pornpawee was a runner-up to fellow Thai Nitchaon Jindapol in the 2018 Thailand Masters - also a BWF Super 300 event. She has also won three BWF International Challenge titles.
Marin had beaten two Thai players in the tournament - Phittayaporn Chaiwan in the quarter-finals and Supanida Katethong in the semi-finals.
Marin, who is still looking for her first title of 2020, also lost to Thailand’s Ratchanok Intanon in the Indonesia Masters final last month.
Marin, 26, won the Olympic gold medal at Rio 2016 and is a three-time world champion (2014, 2015 and 2018).
Rising Thai star Kunlavut Vitidsarn lost to top seed Viktor Axelsen of Denmark in the men’s singles.
It was the 18-year-old’s first appearance in the final of a BWF World Tour Super 300 tournament. Kunlavut completed a hat-trick of world junior titles last year.
Earlier, Greysia Polii and Apriyani Rahayu of Indonesia bagged the women’s doubles crown after they battled past Gabriela and Stefani Stoeva of Bulgaria 18-21, 22-20, 21-17 in one hour and 36 minutes.
Kim Sa-Rang and Kim Ha-Na claimed the mixed doubles crown after they defeated sixth seeds Thom Gicquel and Delphine Delrue of France.
The Korean pair rallied after losing the opening game 21-15 to win the next two 21-11, 21-10 in 61 minutes.
Top seeds Lee Yang and Wang Chi-lin of Taiwan were to play fourth seeds Kim Astrup and Anders Skaarup Rasmussen of Denmark in the men’s doubles decider - the last final of the tournament.