Once viewed as the future ruler of the heavyweight division, the towering Ukrainian had become the subject of criticism after knockout defeats to Corrie Sanders and Lamon Brewster. Another loss would have left his hopes of returning to the top of the division in serious doubt.

Peter (24-0 (21 KOs) was one of boxing’s hardest punchers and one of the heavyweight division’s fastest-rising contenders. Nicknamed “The Nigerian Nightmare,” he was favored by many to expose Klitschko’s suspect chin and earn a world title shot.

An IBF and WBO heavyweight title eliminator was on the line, with the winner becoming the mandatory challenger for a world championship. For Klitschko, it represented a chance to revive his career. Peter had the opportunity to announce himself as the heavyweight division’s next rising star.

From the opening bell, Klitschko displayed the disciplined style that would later define his championship reign under trainer Emanuel Steward. He controlled the range with a stiff jab, straight right hands and constant movement, while tying Peter up whenever the Nigerian closed the distance. Peter continued pressing forward in search of a fight-ending punch but struggled to consistently get inside.

Everything changed in the fifth round.

Peter landed a looping right hand that dropped Klitschko to the canvas. Although the punch appeared to land partly behind the head, referee Randy Neumann ruled it a knockdown. Less than a minute later, Klitschko went down again after another exchange, reviving memories of his previous knockout defeats.

Unlike those earlier setbacks, Klitschko survived the round and regained control of the fight. He returned to working behind his jab, landed straight right hands and forced Peter to expend energy trying to close the distance.

Peter remained dangerous throughout the contest. A hard right hand in the eighth round shook Klitschko, and another crushing right hook followed by a straight right sent him to the canvas for a third time in the 10th. Once again, Klitschko beat the count and boxed his way out of danger.

By the championship rounds, Peter’s relentless pressure had begun to slow. His face was badly swollen, and his attacks became less effective. Peter briefly stunned Klitschko with a wild left hand early in the 12th, but Klitschko answered with a sharp left hook that backed Peter up before finishing the fight strongly.

CompuBox statistics showed Klitschko landing 204 of 523 punches (39%), while Peter connected on 100 of 440 (23%). Despite being knocked down three times, Klitschko out-landed Peter by more than two-to-one over the 12 rounds.

All three judges scored the bout 114-111 for Klitschko, giving him a unanimous decision victory. HBO unofficial scorer Harold Lederman also scored the fight 114-111 in Klitschko’s favor.

The victory earned Klitschko a shot at IBF heavyweight champion Chris Byrd, whom he stopped in seven rounds the following year to capture the title. That victory launched one of the longest and most dominant heavyweight championship reigns in boxing history.

Peter absorbed his first professional defeat but remained a major contender. He rebounded with victories over James Toney before capturing the WBC heavyweight title in 2008, although the Klitschko fight exposed the technical shortcomings that later troubled him against elite opposition.

The rivals met again in 2010 under much different circumstances. By then, Klitschko had established himself as the division’s dominant champion, while Peter entered as the challenger. Klitschko controlled the rematch from the opening rounds before stopping Peter in the 10th, completing a rivalry that began with one of the heavyweight division’s most memorable fights of the 2000s.