"After the second, third and fourth rounds you're saying 'it can't go on like this' and yet it does."
BBC Radio 5 Live's Mike Costello is still in awe of what Diego Corrales and Jose Luis Castillo served up in May 2005.
The 10th and final round probably appears in more social media feeds than any other. People somehow connect with a beaten man summoning something from somewhere to turn the tables.
Two years later to the day, Corrales - the victor - would be tragically killed.
"He made his mark in boxing that night," says Costello. "If anyone says to me this is their number one fight of all time, then I can be persuaded."
A fight with lasting damage
Each man took a lightweight world title into the fight at the Mandalay Bay in Las Vegas, and Corrales also brought a turbulent recent history.
He had been imprisoned for 14 months three years earlier for assaulting his then-pregnant ex-partner. Following his last fight before prison he fired his dad from his corner for stepping in to stop a bout with Floyd Mayweather, who had floored Corrales no fewer than five times.
Despite a run of wins after his release, Corrales was told by his father that Castillo would prove too much, citing the Mexican's bigger natural size.
To counter that, a plan was devised to fight up close - 'on the inside', in boxing parlance. There were cuts, swellings and bruises on display by halfway.
"Sometimes you are safer on the inside," says Corrales' trainer Joe Goossen as he watches the opening rounds back.
"I don't know how both these guys stood up to these punches."
Corrales was left so sore he needed his wife Michelle to tie his laces in the weeks that followed.
BBC Radio 5 Live analyst Steve Bunce says: "You can have a good career and never get hit that much. That is the type of fight that does damage both of the men involved in it."
'All spent out in Hollywood'
For nine rounds the fight showcased enough of the fighters' craft and durability to place it among the classics. After 10 rounds it had moved to a status attained by only a handful of other contests.
"I think that 10th round is one of the greatest rounds I have seen, if not the greatest I have ever seen," Bunce reflects. "This fight is just about as pure and as good as it can possibly get."
Dumped to the canvas by a left hook early in the round, Corrales' mouth guard slips out for the second time.
Seconds later a left hook-right uppercut combination floors him again. This time he pulls his mouth guard out and stands at the count of nine.
Acclaimed referee Tony Weeks says he still thinks of being in the middle of that fight every day. He docked a point from Corrales for the repeated mouth guard infringement. The fact Corrales contested the decision was enough to convince his corner he was still clear-headed.
Asked whether the guard was replaced a little more slowly on the second occasion, Goossen recalls: "I'm not going to argue with that." Time was bought for his charge to recover.
Backed to the ropes and all but beaten, Corrales lands a desperate left hook which somehow turns the tide. As Castillo's head rocks back and forth under attack, he is stopped on his feet. From the jaws of defeat, Corrales has won. Fittingly, he spits out his mouth guard while raising his hand.
"It is one of the great moments of my life right there," says Goossen, who raced into the ring to lift his fighter. "This one had every element you could dream up in a Hollywood movie. I think he spent it all that night and I don't know how much he had left after the fight, to tell the truth."
Tragedy and motivational legacy
Castillo won a rematch between the pair and boxed for nine more years without ever regaining a world title. Corrales - still bruised when he began training for the rematch - lost the final three fights of his career and was killed in a motorbike accident aged 29.
"I was floored, absolutely floored," says Goossen. "I always dreaded that motorcycle he drove.
"Everybody who was anybody turned up at the funeral and I felt so horrible for his wife Michelle, who is a wonderful woman, and his kids."
Corrales' victory provides a yardstick against which other all-action bouts can be measured. Some even take footage of round 10 and post it online along with motivational messages about never giving up.
"You'll be hard pressed to ever see a fight like that happen again," Goossen concludes. "I don't know if they'd allow a fight like that to go on again.
"It deserves to live in history."