Jeff Horn has made weight by just 160 grams for his voluntary WBO welterweight title defence against Gary Corcoran.
Horn weighed-in at 66.52kg during Tuesday's weigh-in at the Brisbane Convention and Exhibition Centre, having woken up the previous morning at 70.4kg.
British opponent Corcoran also come in under the prescribed welterweight limit, tipping the scales at 66.47kg.
Horn will spend the next 24 hours refuelling and rehydrating and will be several kilograms heavier by the time he steps into the ring.
"I'm very relieved," Horn told reporters. "It's always good to get in nice and close to that weight but not go over it, because it can be stressful.
"It's always a struggle ... (but) I've done this plenty of times before. I feel like I'll be feeling good tomorrow.
"I'm going to have a good feed tonight and just relax, watch a movie, have a nice sleep, get up and do the business."
Corcoran's co-trainer Peter Stanley suspects such a dramatic drop could drain Horn of energy in the later rounds.
"No doubt, he had to suffer," Stanley said. "The more times you go to the well the more times you're going to struggle.
"I'm not saying he's going to struggle - tomorrow night he's going to be a big, big boy, another five or six kilos for sure.
"Will it make him suffer in the fight? We'll see." Corcoran had no such troubles, weighing in at 66.47kg.