Answer
The Ukrainian professional boxer, Wladimir Klitschko, holds the prestigious title of being the first boxer to defeat the formidable Ruslan Chagaev in a professional boxing match. This significant event occurred on June 20, 2009, in the Esprit Arena in Düsseldorf, Germany. Klitschko demonstrated his exceptional skills and relentless determination throughout the fight, ultimately securing a victory over Chagaev and etching his name in boxing history.