Will, who has been in training with the Waihi Beach Surf Lifesaving Club's little nippers programme for four years, said the much larger man was yelling for help as they got close to him.
He then tried to grab the boys to stay afloat as they battled against the rip to get back to shore.
"We were trying to encourage him to come in," said Sergio.
"But he was only just moving and the waves would hit him and he'd go under."
The rescued man last night told the Herald he feared the worse.
He said that the boys had saved his life, and he was looking forward to meeting them.
"I definitely want to say something to them ... they are certainly heroes for me," he said.
Vincent said he was caught in a strong current and swept out to sea.
"It was a full moon tide and the current was too strong, it felt like I was in a deep hole and then I was about 60 metres from the beach."
He was guided back to shore by the boys, taken to hospital, and discharged after three hours.
The boys' actions were greeted yesterday with praise.
Asked if they felt scared or worried for their lives at any stage, Will said: "Nah, not really".
Waihi Beach Surf Lifesaving Club captain and police sergeant Dave Litton said the two boys' bravery was remarkable, particularly because they were small and were fighting a 1.5m swell.