Scoring the lone goal for Brunei in their win over Timor Leste on Monday night, the teenager's instinctive reaction to a cross from captain Md Najib Hj Tarif saw the country through to the semi-final of the Hassanal Bolkiah Trophy (HBT) for the first time since the inaugural edition in 2002.
"It was just like in training ... We do that all the time," said the 17-year-old yesterday.
"But of course, I was still nervous.
"At first I didn't know I had scored but then I saw the rest of the team celebrating ... and it hit me," he grinned.
Poking home Md Najib's cross from the left in the 18th minute, the midfielder's strike hands Brunei a semi-final clash against Myanmar tonight a team many have dubbed as tournament favourites.
A Brunei Youth Team player since 2009, Md Aminuddin started playing organised football in 2007 with Muara Vella Academy one of the most successful clubs in the country in terms of grooming young players.
Md Aminuddin also found the net during Saturday's 3-0 win over Malaysia, scoring the Sultanate's second goal to hand them a comfortable cushion after 18 minutes.
Coincidentally, Md Aminuddin, who wears jersey No 18, also scored in the 18th minute against Timor Leste.
A student at Menglait Secondary School, he started all four of Brunei's Group A games at the Hassanal Bolkiah National Stadium in Berakas.
Monday night's game was different though with fans hard pressed to remember the last time they were refused entry to the 25,000 capacity venue.
"There were a lot of spectators at the stadium I've never seen so many people there before," said Md Aminuddin.
"It was as if it was back to 1999 (the year Brunei won the Malaysia Cup). It was just like the old times.
"It felt great!
"Although I've never been there (Hassanal Bolkiah National Stadium) during that time, I've heard the stories," he added.
No doubt, more stories will be created tonight.The Brunei Times