| England's David Haye has vowed he will quit fighting come his 31st birthday in October [GALLO/GETTY]
David Haye must rely on his blistering speed against the reach and power of Wladimir Klitschko as the two go head-to-head in a much anticipated heavyweight title fight.
The trash-talking Englishman has been looking for a fight with Klitschko or his older brother, Vitali, since he moved up from the cruiserweight division in 2008.
It's finally happening on Saturday in the Imtech Arena football stadium in Hamburg.
Klitschko, the IBF and WBO champion, is the bookmakers' favourite in the unification bout.
"I am very happy with my weight, this is my ideal, perfect fighting weight"
WBA Champion David Haye
Standing at 6-foot-6 (1.99 m) - 3 inches (8 centimeters) taller than his opponent - he has the reach advantage.
Klitschko weighed in on Friday at 110 kilograms (242.5 pounds), compared to 96.5 kilos (213 pounds) for Haye. In the customary stare-down, Haye smirked at his opponent who remained stone-faced.
"It's the first time I got on the scales for a long time," Haye said.
"I wanted to make sure I was eating perfectly, healthy, organic, homegrown, I am very happy with my weight, this is my ideal, perfect fighting weight."
Klitschko is four pounds lighter than for his last bout against Samuel Peter in 2010, while Haye is 2-1/2 pounds heavier than for his last bout against Audley Harrison last November.
War of words
Undefeated in seven years, the Ukrainian tends to wear down his opponents with his jab before hammering them with a right cross.
Haye, 30, has sought to rile his older opponent - Klitschko is 35 - in the leadup to the fight with taunts that go beyond the typical trash talk between boxers.
Haye (25-1, 23 KOs) has promised to injure him, refused to shake his hand and worn a T-shirt depicting the severed heads of the Klitschko brothers.
Haye claimed the WBA belt in 2009 by defeating 7-foot-2 Russian fighter Nikolai Valuev, whom he had described as a "hairy freak" and a "circus act."
|Haye already has brother Vitali Klitschko on his radar for next fight [GALLO/GETTY]
Klitschko called the Briton's behaviour "childish" this week and vowed to make Haye "No. 50" in his list of knockout victims.
"He doesn't give any respect, but that's his personality," Klitschko said after a workout in Hamburg.
"I believe he's not such a bad person, he just lost his mind after beating Valuev."
"He flies above the ground. So my goal, and this is what I'm going to do on July 2: put his feet on the ground. I think it's going to be good for him."
Many boxing fans say Haye has brought energy and excitement to a heavyweight division lacking strong profiles during the long reign of the Klitschkos. Haye calls the brothers "frauds," saying they've kept their belts by taking on lacklustre opponents.
While that's a stretch, it's clear that Klitschko faces a career-defining moment against Haye, considered his strongest challenger yet. The Hamburg crowd will favour Klitschko, a fluent German-speaker, though Haye can count on the support of thousands of travelling British fans.
Although both fighters are outstanding athletes, it remains to be seen who has the stronger chin. Haye has been knocked down by Lolenga Mock, Carl Thompson, Jean-Marc Moremec and Monte Barrett, but came back to win each time except against Thompson.
"I'll start thinking about Vitali after the referee has counted to 10 on Saturday and I'm the new unified champ"
A confident David Haye
Klitschko was beaten by knockout in fights against Corrie Sanders and Lamon Brewster in 2003 and 2004. He was downed three times but came back to win on points against Nigerian Samuel Peters.
If Haye wins, there's a narrow chance he could line up one last fight with the elder Klitschko brother, Vitali, before he turns 31 on October 13.
Haye has stated that he will retire on his 31st birthday. Vitali is the WBC champion, the only belt that Saturday's combatants don't have.
"I'll start thinking about Vitali after the referee has counted to 10 on Saturday and I'm the new unified champ," Haye said.
"There's nobody else I want to fight."