[1][3] In 2006, Grachev moved to San Diego, California, United States with Evgeny Khil — long-time friend and fellow kickboxer — after appointing Mark Dion of City Boxing as his manager.
[4] Due to the lack of popularity of kickboxing in the United States, Denis Grachev eventually made the full-time commitment to boxing in 2011 and is primarily trained by former IBF minimumweight world champion Manny Melchor.
[7] The following year in WAKO's Amateur World Championships in Szeged, Hungary, Grachev won the gold medal under full contact rules, also earning the classification of International Master of Sport in kickboxing.
On September 13, 2006, he won WBKF's vacant Commonwealth of Independent States -81 kg championship under international/low kick rules when he defeated Denis Goncharenko of Belarus.
On July 4, 2011, Grachev went on to capture his first major championship in boxing when he defeated Eddie Caminero with a third round TKO and becoming the WBC Continental Americas light heavyweight champion.
Though some believed that Grachev won the majority of the rounds (and therefore the fight) with his sheer aggression and the fact that he landed more punches,[18] most analysts and ringside observers agreed and believed that Bute had the upper hand throughout the bout, as he out-boxed Grachev throughout a majority of the rounds of the fight and managed to land the harder punches of both of the fighters.
[19][20] On March 30, 2013, Grachev added another big name to his boxing resume when he fought Zsolt Erdei in a 10-round fight and defeated him via split decision.