I'm tempted to still believe this is true. Petrosyan beat Ngimbi by decision, Buakaw went on to knock him out in the first round. The last five years, Petrosyan has a better record, but apart from Allazov, the level of their competition has been quite similar the last five years.
Buakaw:
Artem Pashporin x2
Dylan Salvador
Sergey Kulyaba
Nayanesh Ayman
Jonay Risco (robbed)
Victor Nagbe
Marouan Toutoh
Chris Ngimbi
Petrosyan:
Jauncey
Pashporin
Jordan Watson
Ngimbi
Nattawut x2
Sorgraw
Allazov
Petchmorakot (i only count their second fight as a win for Petrosyan)
Samy Sana
Currently i'd probably rank them like this:
1. Sittichai
2. Marat Grigorian
3. Petrosyan
4. Buakaw
5. Tayfun Ozcan
6. Endy Semeleer
7. Superbon
8. Davit Kiria
9. Marouan Toutouh
10. I don't know this one, probably Allazov but i think Petchmorakot can also be considered for beating Petrosyan in their first fight.
I think Marat Grigorian would beat petrosyan by KO in a 5 round fight. Petrosyan vs Sittichai would probably be close, with Sittichai taking the edge. I still regard Sittichai higher than Marat, because although he lost, he was still better 4 times out of 5.
Samy Sana became hyped because he beat Yodsanklai, but it's not a very significant win. Even Diesellek, Sorgraw and Nattawut beat him.
Allazov is very skilled and on a winning streak, but his only really big win in the last five years might be against Pikeur.
Buakaw VS Ngimbi was in a 1 round , 9 minutes in Cambodia under MAS rules ( Muay Thai , weird Tekken gloves , KO only to win and throw allowed ) .
Buakaw may have won by KO but nothing suggest that Petrosian wouldn't be able to KO Chris .
Yodsanklai could have finished Chris but he took pity .
We can't compare Petrosian VS Buakaw last year , make no sense .
Buakaw beat Sergey , Salvador , Pashporin and Victor Nagbe in MT rules .
Buakaw only win in KB are Risco and Toutoh .
If we go by only KB rules then Buakaw isn't even top 10 of the last 5-10 year , in fact since the Khel rematch Buakaw has been semi-relevant when it comes to KB rules .
His biggest fight in KB rules ( after 2014 ) was against Yi Long....
If right now Buakaw fight Petrosian the only way he win is in a 5x3 rounds and full Muay Thai with all the throw and scoring criteria .
No way slow Buakaw will out-point Petrosian ( I think he can KO Petrosian but would need all the luck to land that blow especially his very potent left hand ) in a 3 round KB fight .
Petrosian records isn't exactly unbelievable either in the last 5 year :
Beat Sorgraw ( who has 0 fight under KB rules and after that has 1 fight this one....) who is a very inconsistent former Lumpini champion as hell in a 3 round fight in KB rules ( no way Sorgraw would of won it ) .
Beat Jo Nattuwot twice , Jo is a destroyer but he got no experience in KB rule , it was not enough in the first fight and signing him for the second was ill advised .
Beat Petchmorakot ( clinch and elbow specialist LMAO ) , in a rematch under even more limited rules ( up there with current K-1 rules , even GLORY rules were more fair than Petchmorakot VS Petrosian ) .
Beat Pashporin , good prospect .
Beat Jouncey , elite prospect but after that fight he is way better now .
Beat Jordan Watson ( not a great win under KB rules ) .
Beat Samy ( who looked really great in KB after the two domination of Yod and Askerov ) .
Beat Allazov ( easily the best win of the past five years ) .
Superbon record in KB is more impressive than Petrosian in the last 5 years :
Jomthong ( who looked very good in KB and Int MT , he hasn't been stopped by anyone previously in MT or KB rules ) .
Dzianis Zuev ( pure domination ) .
Davit Kiria .
Sittichai ( nothing greater than that ) .
Wilson Varela ( schooled a guy that outclassed the destroyer Lumpini Champion Yussef ) .
Mohamed Khamal ( shut him down ) .
Nayanesh Ayman 2X .
Marouan Toutouh .
Cedric Manhoef .
Khayal Dzhaniev .
Artem Pashporin .
Sergey Kulyaba .
Superbon loss to Marat and Endy were in tournaments so not really surprised ( can happens to anyone ) .
Very hard to say right now who is top 10 at 70 KG because of how inconsistent KB is :
Should Buakaw even be ranked in the top 10 KB ?
Sittichai will currently fight in MT rules so how will he be under KB rules right now ? Is he even with GLORY anymore ?
What about Yodwicha ? He was like Petchmorakot before fighting Petrosian , no one think he would be any good in KB ( he also beat Superbon in the amateur MT rules and did so if my memory is correct with very few clinching , he most likely beat Superbon again or any other Thai in KB or MT rules right now ) .
Petrosian ducked GLORY and Kunlun for the past 5 years and went to ONE FC that is ( arguably ) way easier than GLORY and Kunlun .
Petrosian didn't fight allot of the top names it's crazy ( Sittichai , Yodsanklai , Superbon , Marat , Beztati and Ozcan ) .
Sorgraw , Petchmorakot , Sana , Jo were basically green under KB rules , they didn't even have enough time to progress and sharpen their skills in KB rules that Petrosian beat them .
He did that to Kem too and almost did that to Yodwicha .
That's why Petrosain can't be KBer of the decade , too much running around the best of the moment and cherry picking his opponent as favorable as ever .
Sittichai fought everyone that mattered and did so when they were at their best in KB rules ( apart from Souwer ) .
He didn't beat semi-green Muay Thai fighter turned KBer ( for the occasion only ) like Petrosian did .
And even when Petrosian did that he still found a way to lose LOL .
Sittichai record is next level insanity :
Yi Long .
Marat ( 4 times ) .
Baya .
Beztati .
Souwer .
Murthel .
Superbon .
Risco .
Gogokia ( twice ) .
Jouncey ( twice ) .
Askerov .
Khel .
Salvador ( twice ) .
RVR ( twice ) .
Kiria ( twice ) .
Allazov .
And he also called Petrosian out for year , while also ALMOST fought Yodsanklai ( who looked nigh-invincible at the time ) both of them in KB rules .
Sittichai career in KB ( without event talking about MT ) is arguably top 5 ever at 70 KG .
Funny that in your top 10 at 70 KG ( again depends ) 4 guys are fighting in MT rules right now ( Petchmorakot , Buakaw , Superbon and Sittichai ) .
Right now my top 10 at 70 KG ( KB rules only )
1 Marat .
2 Superbon .
3 Petchmorakot ( he won't be fighting in KB anymore ) .
4 Sittichai .
5 Petrosian .
6 Beztati .
7 Jouncey .
8 Allazov .
9 Ozcan.
10 Gashi .