The informal drills turned into daily training - now she doesn't want to stop.
"Sometimes I forget and she'll remind me we haven't done training yet. It's incredible the things she's picked up in a year."
When asked if he was worried about the impact of boxing training on his daughter's young body, or the risk of injury, Falefehi says her health always came first.
"I don't push my daughter - we just have a bit of fun. It's like 20 minutes a day and in the weekend we don't train."
Falefehi says Lesli is a shy girl but her boxing skills have given her extra confidence as she begins primary school in Queensland.
"She shows off a bit in front of her friends, but she's never got in trouble for fighting," he says.
"I used to let her punch me in the face with her gloves on. Now I don't because of the power she's got."
Falefehi says he'd like to see his daughter continue with her boxing and he'll support her if, one day, she decides she wants to get in the ring.
"I see a lot of potential in her and hopefully she keeps at it. But if she finds a new hobby she's good at, I really don't mind, as long as she's happy."