In 2006, Graham had a feud with Badr Hari in K-1 World Grand Prix 2006 in Auckland. Hari mocked Graham as a has-been, and Hari as the future. A brawl at the press conference instigated by Hari kissing Graham hyped up their match.[3] The real match was won by Peter, who won by knockout via his trademark "Rolling Thunder" spinning kick, which broke Hari's jaw.[4] Hari was sidelined for almost a year. On 5 August 2007, Graham and Hari met for a revenge fight in K-1 World GP 2007 in Hong Kong as one of the three super bouts of the event, held in Hong Kong for the very first time. This time, Hari was more alert to the threat of a Rolling Thunder by Graham. Both fighters could not show their top performances as Hari won the fight by points. Graham tried the Rolling Thunder Kick twice in the last moments of the fight, but could not connect with Hari.[6]