In his next fight, on 20 February 2009, Martirosyan knocked out Thailand's Kiatchai Singwancha for the PABA middleweight title.
on June 27, 2009 he faced his biggest challenge yet in fighting the undefeated future interim champion Hassan N'Dam N'Jikam.
Back in St Petersburg and a recovery win later, Martirosyan fought for the vacant WBO European middleweight title.
After knockout wins over Aziz Daari and Vitor Sa, he became WBOs number one ranked middleweight contender.
In 2017, after four years of inactivity, Martirosyan made a comeback, defeating Georgian Nikolozi Tasidis Gviniashvili by decision in Germany.