HAMBURG, Germany » David Haye must rely on his blistering speed against the reach and power of Wladimir Klitschko 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 today in the unification bout at Imtech Arena in Hamburg.

Klitschko, the IBF and WBO champion, is the favorite (55-3, 49 KOs), and at 6-foot-6, has a 3-inch height advantage.

Klitschko weighed in Friday at 242 pounds, compared to 213 pounds for the 30-year-old Haye.

In the customary stare-down, Haye smirked at the stone-faced Klitschko, as throngs of raucous British fans booed and heckled the Ukrainian.

“Me and Wladimir don’t like each other. You’ll see that in the fight,” Haye said.

Undefeated in seven years, Klitschko tends to wear down his opponents with his jab before hammering them with a right cross. Haye said the first rounds would be crucial.

“I’ve got to make sure I land my bombs and he doesn’t land his, plain and simple,” he said. “I can’t afford to be getting pumped in the face by his big jab.”

WBA champion Haye has sought to rile his opponent in the lead-up 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.”

Klitschko has called the Briton’s behavior “childish” and promised to respond in the ring.

“David Haye will of course pay for everything during the fight,” Klitschko said Friday. “David Haye will be No. 50 on my knockout list. That’s what is going to happen.”

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 lackluster 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 favor Klitschko, a fluent German-speaker, though Haye can count on the support of thousands of traveling British fans.

“David Haye has all the attributes to win, and win with a knockout,” said Steve Victor, a 27-year-old IT consultant who traveled from London to watch the fight. “Speed, agility; his technical ability is better than any other in the division.”

While 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 Mormeck and Monte Barrett, but came back to win each time except against Thompson.

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 Samuel Peters.

If Haye wins, there’s a narrow chance he could line up one last fight with the elder Klitschko brother, Vitali.

“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.”