PHOTO: AFP
Rising star An, who is ranked 50th in the world, roared back to defeat Tai 14-21, 21-18, 21-16 in 66 thrilling minutes in the Chinese city of Nanning.
Taiwan and title-holders South Korea were already into the quarter-finals of the mixed-team world championships, but this was further evidence of An's precious talent.
China, Malaysia, Japan and Thailand are also into the knockout stages.
The teenager An, who won the New Zealand Open earlier this month, said: "My strategy was to defend in the beginning of each rally and then to take my opportunity.
"My coach advised me to pay attention to the front and keep the rally going.
"I'm surprised I could beat her."
The 24-year-old Tai said that she had a niggling injury but did not use that as an excuse.
"She's tall, powerful and has very good footwork," the Taiwanese said of her young opponent, who only turned 17 in February.
"She's good in all aspects of the game. She will be an outstanding player in future for sure."
China eased to victory to send India home and propel themselves and Malaysia into the last eight.
The hosts are yet to drop a match in Nanning, hammering Malaysia 5-0 in their opener and then dismissing India by the same comprehensive scoreline.
Along with top seeds Japan, China — the 10-time winners of the Sudirman Cup — are the favourites to lift the trophy on Sunday.
Saina Nehwal, India's 2015 world silver-medallist, was well beaten by Chen Yufei, the third-ranked Chinese winning 21-12, 21-17 in 33 minutes.
"I have had some trouble with my wrist and ankle and didn't want to push too hard," said the defeated 29-year-old, pinpointing Tuesday's loss to Malaysia as being fatal to India's hopes.
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