The Spanish Olympic gold medallist won her first event since 2019, as Viktor Axelsen continued his winning run in the men's final.
The reigning Olympic champion was dominant against World No. 1 Tai Tzu Ying from the off, winning the Super 1000 event 21-9, 21-16.
However, Chinese Taipei top seed Tai wasn't helped by some stomach discomfort, which forced her to take a two-minute time out in the opening game.
But having lost her three previous final appearances, reigning Olympic champion Marin was in no mood for mercy and ruthlessly dispatched her opponent to close out the opener.
Tai managed to find some rhythm in a more competitive second game, but a determined Marin finished the contest on her first of four match points.
For Marin, it was an emotional first victory since the death of her father last year. After the game, she turned to the camera to say
'Te quiero, papi' or 'I love you, daddy'.
Viktor Axelsen went into the men's final against as the heavy favourite, having never even conceded a game in eight previous encounters with Ng Ka Long Angus.
Despite a spirited performance from the Hong Kong seventh seed, Olympic bronze medallist Axelsen continued that record with a 21-14, 21-14 win.
After racing to an early 5-point lead in the first game, the Dane may have hoped to steamroll his initially predictable opponent. But Ng rallied and was started to cause his taller opponent some problems at the net.
But 27-year-old Axelsen was able to find another gear to finish the match off, and claim his second-consecutive Super 1000 tournament victory.
There was joy for the hosts in the mixed doubles final, where Dechapol Puavaranukroh and Sapsiree Taerattanachai were victorious.
The top-seeded Thais beat Indonesian pair Praveen Jordan and Melati Daeva Oktavianti 21-3, 20-22, 21-18 in just under an hour.
But it wasn’t long before Indonesia gained their revenge, as Greysia Polii and Apriyani Rahayu dominated host shuttlers Jongkolphan Kititharakul and Rawinda Prajongjai 21-15, 21-12 to lift the women’s doubles trophy.
In the men’s doubles final, Taipei’s Lee Yang and Wang Chi-Lin edged Malaysian Olympic silver medallists Goh V Shem and Tan Wee Kiong in a thrilling encounter.
Lee and Yang, who celebrates his 26th birthday tomorrow, took the first game 21-6, before their opponents hit back 21-23 in the next. But the sixth seeds held their nerve to close out the deciding game 21-19 and take the spoils.
“Of course he knows it’s my birthday tomorrow, because we’ve been classmates since elementary school, we’ve known each other since we were 10 or 11,” Wang told the BWF website after.