Anthony Joshua on Friday weighed in more than 20 kilograms (44 pounds) lighter than heavyweight champion Andy Ruiz Jr ahead of their controversial rematch in Saudi Arabia.
The leaner and meaner British boxer seeks to win back the IBF, WBA and WBO titles that he lost to Ruiz in a shock June defeat in New York in a high-profile duel on Saturday, dubbed "Clash on the Dunes".
Joshua weighed in much lighter compared to their June encounter, hitting the scales at 16 stones and 13 pounds (107.5 kg) ahead of the fight, seen as the biggest test of his boxing career.
Ruiz, sporting a Mexican sombrero hat, tipped the scales at 20 stones and three pounds (128.36 kg), heavier than what he weighed in their June encounter in New York's Madison Square Garden.
Joshua weighed in at 247.8 pounds (112.4 kg) in June, but the boxer has shed muscle mass in order to improve his mobility around the ring.
"Before I was trying to bench press a house. I used my body to get where I needed but then I started realising the sweet science of the sport," Joshua said.
"I am punching like a horse kicking backwards right now."
The stakes could not be higher for Joshua, who would face a long road back to the pinnacle of the heavyweight division if he loses Saturday's much-hyped fight.
Victory, by contrast, would re-establish his credentials in the division, opening the door to money-spinning fights against WBC champion Deontay Wilder or fellow Briton Tyson Fury.
Ruiz says he is ready to take on the British challenger despite his increased fitness.
"I know he's lost weight and will try to box me around, but it's just my job to prevent that," Ruiz said earlier this week.
"I'm ready for whatever comes my way."
The rematch will be taking place in a purpose built 15,000-seat arena in Diriyah on the outskirts of the Saudi capital Riyadh.
Saudi Arabia secured the staging rights to the rematch after reportedly offering an astronomical purse to promoters and fighters.
Joshua's take is reported to be around $60 million while promoters Matchroom Boxing were handed an eye-popping $40 million site fee to award the fight to Saudi Arabia.
Ruiz, who was locked into a rematch at a set figure as a condition of his first meeting with Joshua, is expected to receive $9 million.
Meanwhile, Mexico President Andres Manuel Lopez Obrador wished Ruiz, who was born in the United States to Mexican parents, well for the fight.
Lopez Obrador, a leftist populist who took office last year, said in a video posted on Twitter: "I wish you all the best tomorrow in Saudi Arabia."
Pointing to a Mexican flag -- whose seal portrays an eagle devouring a snake -- Lopez Obrador told the 30-year-old boxer: "You represent the Mexican people, our beloved country, home to your parents, grandparents and ancestors."
After Ruiz's June upset, Lopez Obrador invited him to the presidential palace in Mexico City, where he said he admired his "sacrifice, struggle, perseverence and stubbornness."