Back when Tiffany Teo was in school, she used to make her physical education teacher's job a nightmare.
But now, not only is the mixed martial arts (MMA) fighter making her teacher proud, but she is also causing nightmares - to her opponents inside the fighting enclosure.
Since making her professional debut at Singapore Fighting Championship 2 on Feb 20, the 27-year-old - who represents the Juggernaut Fight Club - has been unstoppable.
Last month, she scored her biggest triumph on her One Championship debut, forcing Egyptian Walaa Abbas to tap out to a rear naked choke in their flyweight bout to stretch her win-loss record to a perfect 4-0.
To honour her breakthrough, she is The Straits Times' Star of the Month for November. The award is an extension of ST's Athlete of the Year accolade launched in 2008. Both are backed by F&N's 100Plus.
DO NOT MESS WITH HER NOW
A secondary school teacher, who added me as a friend on Facebook, tagged some of those who would tease me that they have to be careful now.
TIFFANY TEO , an undefeated MMA fighter, jokes about how far she has come since her schooldays, when she would skip PE classes regularly.
Said ST's sports editor Lee Yulin: "It was Tiffany's first appearance under the One Championship banner and it was natural for her to feel nervous taking on the aggressive Egyptian in front of the home crowd. But she displayed a huge amount of grit and determination to hang on for the win.
"Tiffany thoroughly deserves to be the first MMA fighter to win the award."
Yet, her MMA success is a huge contrast to her poor attendance record for PE classes. She recalled that she would dig up excuses after excuses to skip those classes at Greenview Secondary and Serangoon Junior College in order to avoid training under the sun.
She recalled: "I hated the sun and I didn't like to be outdoors. I would find every single excuse to skip PE classes - headache, stomachache, pain here and pain there - everything that you can think of."
She had little interest in music yet she joined the choir in her primary and secondary school days, and the music society club in JC, because she wanted "an easy" co-curricular activity (CCA). Hence, many of her former school-mates could not believe that Teo was the same fierce fighter who grappled, took down and locked her opponent in a submission in front of a 12,000-strong crowd at the Singapore Indoor Stadium last month.
Teo said: "They remembered me as the girl who hated sports and the nerd who became an MMA fighter.
"A secondary school teacher, who added me as a friend on Facebook, tagged some of those who would tease me that they have to be careful now," she added with a laugh.
Her rapid progress has also surprised Teo herself, as she made her transition to MMA only this year.
Her journey to the fighting scene began after she completed her A levels. She took up taekwondo lessons conducted by her friend's cousin at a community centre to "give it a try and to keep fit".
She said: "But it was a bit boring because I was partnering kids and children and holding up pads for them."
But that spell piqued her interest in combat sports. In 2009, she joined Baan Nak Muay gym to give muay thai a shot. She joked: "From facing kids to topless guys. The first class was a culture shock."
It took just six months for her fighting talents to be evident, as a Thai coach at the gym wanted to sign her up for a competition in Thailand. But she turned it down, saying: "It sounded like a crazy and wild idea to me. At that point of time, it was still about fitness."
Fighting, however, remained at the back of her mind and she joined Juggernaut after returning from the United States and completing her degree in psychology offered by the University at Buffalo at the Singapore Institute of Management in late 2012.
And she has never looked back since then. She said: "I grew to enjoy the sport. I came back with the intention that I really wanted to fight."
In retrospect, she is amazed by all the strides she has made so far. She said: "I'm pleased with my progress this year and I'm like, 'How did all of that happen?'"