Nicknamed "The Doctor", he is noted for supreme technical skills, ringsmanship, and defensive prowess which has seen him defeat some of the best strikers in the world while taking little damage.
Pramuk at Lumpinee Stadium in January 2007, he went on a six-year, forty-two fight undefeated streak considered to be one of the most dominant reigns in the history of the sport which was eventually ended by Andy Ristie at Glory 12: New York in November 2013.
They initially lived homeless in Milan, sleeping in train stations and on the streets, but were later taken in by a family in Gorizia who offered them work as night watchmen at their factory.
[8] Inspired by Bruce Lee and Jean-Claude Van Damme martial arts films, Petrosyan decided to begin training in Muay Thai at fourteen years old but was initially turned away from the gym for being too small.
[12] Giorgio Petrosyan started his career as a -54 kg/119 lb bantamweight at the age of sixteen and defeated a local Italian fighter in his February 2002 debut, breaking his toes while doing so.
In his first title fight on November 9, 2003, he scored a third round knockout over Gionata Zarbo to be crowned the Muay Thai Association (MTA) Italian national champion.
Steadily moving up in weight and competition level, he captured the MTA European -65 kg/143 lb Championship by outpointing Fabio Pinca in 2004 before making his only successful defence of the belt in February 2005 with another points win over Shemsi Beqiri in his home town of Gorizia.
He fought to a draw with three-time Lumpinee Stadium champion Pinsinchai in Bologna, Italy on April 10, 2005, but soon returned to the win column and defeated Olivier Tchétché by second round technical knockout in a WMC Intercontinental Welterweight (-66.7 kg/147 lb) Championship match in Nova Gorica, Slovenia on June 25, 2005.
[14] Moving up to middleweight, Petrosyan marked his arrival in the weight class that he would go on to dominate by winning the eight-man 72 kg/158 lb tournament at Janus Fight Night 2006 in Padua, Italy, on December 2, 2006.
[15][16] Petrosyan fought at the historic Lumpinee Stadium in Bangkok, Thailand for the first time on January 23, 2007, where he was also handed the first loss of his career, dropping a decision to Nonthanan Por.
[18] From there, he was offered the biggest fight of his career at that point when he replaced John Wayne Parr, who withdrew after injuring his ribs training with Nathan Corbett, to challenge Buakaw Por.
After a first-round knockout of Behrouz Rastagar in Arnhem, Netherlands on October 13, 2007, he entered the Janus Fight Night 2007 -72 kg/158 lb tournament (the event he had won a year previously) on November 24, 2007.
[23] Following a brief return to the Muay Thai scene with wins over Çağrı Ermiş in Tilburg, Netherlands, on May 24, 2008, and Rafik Bakkouri in Abano Terme, Italy, on June 28, 2008,[24] Petrosyan did not fight again until November when he took to the ring twice within three weeks.
[25] Petrosyan took the World Kickboxing Network (WKN) Intercontinental Welterweight (-69.9 kg/154 lb) Oriental Championship on January 31, 2009, when he stopped David Javakhia with a liver kick inside the opening stanza in Turin, Italy.
Petrosyan dominated all three rounds, and dropped Souwer with a knee to the body in the second, en route to a unanimous decision victory, clinching the coveted K-1 World MAX Tournament Championship.
[36] He earned a unanimous decision win against Kem Sitsongpeenong in a competitive match, the Thai fighter's first under kickboxing the rule set, at Oktagon presents: It's Showtime 2010 in Milan on March 13, 2010[37] but reinjured his hand in doing so and thus two more proposed matchups, a March 27 meeting with Yoshihiro Sato at the K-1 World MAX 2010 –70 kg Japan Tournament in Saitama[38] and a fight with Nieky Holzken at It's Showtime 2010 Amsterdam on May 29, were shelved.
After a clear 10-9 opening round, the reigning champion began really picking the tall Belarusian apart with counterpunches, catching kicks and slipping punches en route to another dominant second frame.
Against Mike Zambidis in the semis, while the short Greek aggressively pursued him around the ring with leaping hooks and haymakers, Petrosyan evaded and further countered him with punches and step knees en route to another UD victory.
[46] Giorgio Petrosyan was initially due to take on Yohan Lidon at Thai Boxe Mania 2011 in Turin on January 29, 2011, but the Frenchman withdrew in advance after conceding that he would be unable to make the -70 kg/154 lb weight limit.
[58][59][60] In January 2012, Petrosyan terminated his contract with It's Showtime, which acted as his management team as well as his promoter, due to them not being able to secure the money he was owed by K-1 for winning the 2010 K-1 World MAX tournament.
"[61][62] Now a free agent, he returned to Italy to fight independently and in his first outing since leaving It's Showtime defeated Abraham Roqueñi via unanimous decision at Yokkao Extreme 2012 in Milan on January 21, 2012.
[63] Then, in a much anticipated match-up with Artur Kyshenko at Oktagon 2012 in Milan on March 24, 2012, Petrosyan once again displayed his dominance, outworking the Ukrainian every step of the way to take the win on all three judges scorecards.
Petrosyan's elusiveness was also on display as he ducked and weaved out of the way of Pinca's punches and answered with a counter strike every time before winning a unanimous decision to advance to the round of eight.
Petrosyan was able to nullify the hard-punching Dutchman by using rangy jabs and lead teep kicks to control the distance while landing power combos at will and took the unanimous points victory to win the third major tournament of his career.
[82] Petrosyan was scheduled to fight Jonay Risco for the ISKA Super Welterweight (-70 kg/154 lb) K-1 Rules World Championship at PetrosyanMania in Monza, Italy on October 14, 2017.
[84] In April 2018, Petrosyan signed with ONE Championship, unveiling their Super Series segment as a figurehead, a venture which would intertwine kickboxing and Muay Thai bouts within their MMA based events.
[85] Petrosyan found himself in the co-main event slot for ONE: Heroes of Honor in Manila, Philippines, squaring off against Lion Fight veteran Jo Nattawut, a bout the Armenian-Italian won with his technical defensive kickboxing expertise via a unanimous decision.
[86] After securing the Bellator Kickboxing lightweight championship on a one-fight stint in July, Petrosyan returned to the Asian stage in November, for ONE: Heart Of a Lion, taking on Lumpinee Stadium Muay Thai champion Sorgraw Petchyindee Academy.
[90] On July 12, 2019, Petrosyan defeated Phetmorakot by unanimous decision to advance to the Grand Prix Semi-Finals, where he was scheduled to face Jo Nattawut for a second time.