"I remembered, I think I went to San Jose," the Northern California delivery driver told state lottery officials, who had publicized that the winning ticket was purchased at a gift shop in that city.
Tran checked his tickets, and the winner was "just sitting in my house, on top of my drawer."
After hugs from family, Tran phoned his boss.
"I'm really sorry boss. I hit the jackpot. I don't think I'm going to come in today, tomorrow, or ever," Tran remembered.
The $648 million jackpot is the second-largest lottery prize in U.S. history. It started its ascent Oct. 4. Lotto officials say 22 draws came and went without winners. Some $336 million in tickets were sold for the Dec. 17 drawing.
The other winner, Ira Curry, is from Georgia and came forward to claim her prize Dec. 18. Lottery officials there say she opted to take the lump sum payment of about $120 million after taxes.
Tran has 60 days to figure out how he wants to be paid.
Tran, who did not say where he lives, said his family likes to visit San Jose because of the city's large Vietnamese population.
While visiting the area to eat and shop, Tran bought 5 Quick Pick tickets from Jennifer's Gift Shop, owned by Thuy Nguyen.
Nguyen will also receive $1 million for selling the winning ticket.
Tran told lottery officials that he saw coverage that the winning ticket had been purchased in San Jose, but had forgotten about his purchase.
"Must be a lucky man," Tran thought.
Then he went on vacation, and forgot about the lottery.
It wasn't until his middle-of-the-night inspiration upon his return that Tran realized he had indeed purchased tickets in San Jose.
He came forward Thursday, 16 days after the drawing, to claim his prize.
Curry, of Stone Mountain, lives in a neighborhood of brick and stucco houses with manicured lawns about 10 miles east of Atlanta. She lives in a two-story home with a two-car garage and a basketball goal in the driveway.
She purchased the ticket at the Gateway Newsstand in the Alliance Center building in Buckhead, a financial center in Atlanta.