All of Hari's wins in 2008 were by knockouts, by beating Ray Sefo in Yokohama, Glaube Feitosa (whom he defended his heavyweight title) in Fukuoka and Domagoj Ostojic in Hawaii. On his next fight in Seoul he qualified for the K-1 World GP 2008 Final by TKO win over the Korean giant Hong Man Choi.

In the quarterfinals on December 6, Hari defeated three time K-1 World champion Peter Aerts by TKO in the second round. In the semis he knocked out Errol Zimmerman and headed to his first K-1 Final against Remy Bonjasky. After suffering a knockdown in the first, Hari was disqualified in the second round for unsportsmanlike conduct by stomping and punching an already downed Bonjasky. First the referee Nobuaki Kakuda issued a yellow card and one point deduction. Meanwhile Hari proceeded to Bonjasky’s corner shouting, and quarreled with his opponent's trainer Ivan Hippolyte who then also approached Hari aggressively, but the officials prevented any further physical contact between them.[7] After the five-minute recovery time elapsed, the doctor reported Bonjasky was seeing double and could not continue. Hari was issued a red card and Bonjasky was declared the K-1 World GP 2008 champion.[2]

In later interviews Badr claimed Bonjasky was acting, and that "Remy's corner was screaming at him to stay down".[8]

After the event Badr was not suspended for his actions, but K-1 has however stripped him of his heavyweight title and his fee for participation in the tournament.[9]

While there were many rumours of his and his opponent's participation, it was finally announced that Badr would face MMA Heavyweight Alistair Overeem in a K-1 rules match on K-1's NYE extravaganza. Hari lost the fight by a left hook KO in the first round within 2 minutes. Part of the fight agreement is that both Badr and Overeem would also fight each other in an MMA match for FEG's DREAM promotion sometime in 2009.