He picked up what he thought was a piece of waste paper that he was planning to throw away after he got off the bus.
But when Nanyang Polytechnic student Bryan Lee took a closer look, he realised that it was actually a 4-D ticket, and that someone might have dropped it unintentionally.
He was right.
It belonged to the wife of storekeeper Neo Hock Wah - and it had a winning number.
The story ended happily, with a Lianhe Wanbao reporter helping to arrange a meeting between the Neos and the 18-year-old student.
This came after the Chinese-language evening newspaper published a story about the couple's missing ticket last month.
Speaking to The Straits Times on Thursday, Mr Neo, 55, said his wife spent $10 on the number "1989" on Nov 7.
DOING WHAT IS RIGHT
I don't think this is anything to be proud of or commended for. Returning a lost belonging is just what I am supposed to do.
MR BRYAN LEE, on his act of returning a lottery ticket he had found to its owner.
It had appeared in a dream he had a few nights earlier.
While heading to Yishun for dinner with their son, Mrs Neo snapped a photo of the ticket to show her husband that she had bought it.
When the 51-year-old housewife was alighting from the bus, she dropped her wallet, and the ticket likely fell out then.
Later that night, the couple found out they had won $2,500, but their ticket was nowhere to be found.
They approached Singapore Pools to find out if they could collect the money with the picture and surveillance footage from the store as proof, but were told they could not do so.
Then some friends suggested they contact Stomp or Wanbao about their story.
When Mr Lee, who had been on the same bus as Mrs Neo that day, read the story, he called Wanbao. Reporter Chua Ke Han put him in touch with the couple.
The two sides met on Nov 19 at a Burger King outlet in Woodlands.
Said the first-year business management student: "My priority was to find the owner. Just because I can collect the (lottery) money does not mean that was the right thing to do."
He told The Straits Times that Mrs Neo said she had been worried and had lost sleep after losing the ticket. So he was very glad he could "make someone's day", he added.
To show their appreciation, the Neos gave Mr Lee a $200 hongbao, which he eventually accepted after declining several times.
Of his gesture, Mr Neo said it was to show his gratitude to the young man for returning the ticket.
Said Mr Lee: "I don't think this is anything to be proud of or commended for. Returning a lost belonging is just what I am supposed to do."
He added that he intends to donate the money to charity.