Nguyen's smiles return after another two golds and records
Giggly Viet swim star throws down the gauntlet, gently
She stopped for every camera that was thrust in her face last night, and even for interviews in English, giggling when complex questions flew right over her head, after her second gold of the night.
The first thing that anyone will tell you about Vietnam's Nguyen Thi Anh Vien is that she is a very sweet girl.
But don't be fooled, even goofy champions don't get to the top merely by laughing at themselves when they slip up.
Nguyen (right) ended Monday's SEA Games swimming programme at the OCBC Aquatic Centre empty-handed and, while she still wore her trademark girly smile, if anyone looked closely, he would have spotted fangs peeking out the side.
She pulled out of the 100m backstroke last night and was unabashed about the reason why.
"I'm out of the 100m backstroke because I wanted to win the 200m freestyle," she said, later.
"I was really bad yesterday, and I want to win - and beat Singapore," she added, flashing her pearly whites.
Nguyen was referring to Quah Ting Wen, whom she had beaten in the 200m butterfly final, the first race of the night, and in emphatic fashion.
Clocking 2min 11.12sec, the win was her fifth gold-and-record feat at the Games, with Quah touching the wall more than three seconds later (2:14.50) in second spot.
Thailand's Sutasinee Pankaew was 0.01 behind Quah to bag the bronze.
Nguyen couldn't stand still at the medal ceremony, her body swaying from back to front, as if she was still submerged in water.
She didn't stop to chat either, after the formalities, jettisoning her gold medal to jump into the training pool as she prepared for the 200m freestyle.
"She is very serious about races here at the SEA Games. She must know how to forget when she wins, and how to remember when she loses," said coach Dang Anh Tuan.
When it was time, the 18-year-old climbed out of the training pool and repeated the gold-and-record feat in the 200m freestyle (1:59.27), finishing ahead of Thai Natthanan Junkrajang (2:00.54) and Jasmine Alkhaldi of the Philippines (2:00.84) in third.
"I've met her and we've spoken a bit, she's a very sweet girl, but she's tough," said Quah, about Nguyen.
"For Team Singapore, it's so easy to get support, we've got our friends and family here... she works very hard, and she's tough," the local champion reiterated.
And the giggly - and tough - Nguyen finally flashed those fangs, when she threw down the gauntlet last night.
"Yeah I'm a little bit tired, I just have to eat, sleep and rest, and I will have power," she said.
And she'll need all the power she can get for the scalp she aims to get.
"I want to beat Tao Li too, in the 100m butterfly," said Nguyen.
"I hope (to beat her in her own race) to win on Friday."
And she flashed her toothy grin.