In perhaps the most notable bout of his early career, he featured as a reserve fighter at the S-Cup Europe 2008 in Gorinchem, Netherlands on 20 September 2008, where he defeated Abdallah Mabel by decision.

[10][11] Grigorian competed in the eight-man grand prix at the K-1 World MAX 2010 West Europe Tournament held in Utrecht, Netherlands on 21 March 2010.

He defeated Bruno Carvalho and Anthony Kane by decision in the quarter-finals and semi-finals, respectively, before losing via a second-round KO to Mohamed Khamal in the final.

Following a disqualification loss to Gino Bourne on 19 March 2011, he rebounded with a first-round KO of Lahcen Ait Oussakour on 9 April 2011, before being invited to take part in the eight-man grand prix at BFN Group & Music Hall presents: It's Showtime "Fast & Furious 70MAX", which was held in Brussels, Belgium on 24 September 2011.

At the quarter-finals stage, he was drawn against veteran Dutch fighter Andy Souwer and was able to take him to an extra round, after which he lost a close split decision.

He put in a spectacular performance against the Congolese Muay Thai fighter, picking him apart before forcing the referee to stop the fight due to a cut in round two.

There was chaos in the ring until trainers from both sides as well as officials broke up the brawl with Grigorian still lying dazed with a deep cut over his eye.