Marin was a surprise winner as ninth seed in Copenhagen a year ago and although she has since risen to number one in the world rankings, an injury-riddled build-up to the tournament had put her participation in Jakarta in doubt.
The Spaniard struggled through the early rounds and rolled her ankle in her third-round match on Thursday but was starting to show her best form as the tournament progressed and looked pain-free and at her peak by the time she faced Nehwal.
The Indian second seed got off to fast starts in both games but Marin was adept at stringing together quick points and she rallied each time to overhaul a woman who was seeking to claim her country’s first ever world title.
Both players produced high-quality badminton befitting of a world final but play was often halted by Chinese umpire Zheng Sanliang, who appeared to be involved in the action as much as the players.
Time and again Zheng warned Marin for flicking sweat away from her body, over-celebrating, taking too long between points and even racket abuse when the Spaniard stopped short of thumping the ground upon losing a point.
Nehwal was also targeted by the official but the players seemed to sense it was best just to ignore or claim they could not hear her in the noisy Istora Senayan arena and decided to play on regardless in the second game.
In the end, Marin proved too strong and was delighted she had taken the gamble to participate in the tournament.
“I didn’t think I would be here when I was struggling with my injuries but my coaches said I should keep training and try to play at the world championships and just do the best I could in the tournament,” Marin said in a courtside interview.
“I knew from the beginning it was going to be a very tough match because Saina is really good but I kept fighting until the end and am very happy with my performance today.”
However, Marin’s moment to savour her stunning victory was slightly marred by an anthem gaffe at the medal ceremony.
Draped in her country’s flag, the 22-year-old looked slightly embarrassed but put on a brave face when the Franco-era Spanish national anthem, instead of the modern one which does not contain any lyrics, was played in the arena.
The Badminton World Federation (BWF) moved quickly to apologise for the error and released a statement soon after the ceremony.
“The Badminton World Federation and the local hosts for the BWF World Championships have apologised to Carolina Marin for playing the incorrect version of Spain’s national anthem today,” it read.
“The BWF and the hosts, Indonesia Badminton Association, sincerely regret this unfortunate mistake.”
(Reporting by John O’Brien in Singapore; Editing by Sudipto Ganguly)