The connecting record
shownOne Punch Man · ch. 10
Carnage Kabuto beat Genos in One Punch Man.
What each of them is ranked on
The winner · Carnage Kabuto · rank 12
Broke the left side of Genos's face with one punch, then blew the cyborg's own fire blast back into him to finish his part in the fight — and became the first thing in the series to read Saitama correctly, leaping the width of the room rather than swinging, and asking him where the strength came from. Went into Carnage Mode on hearing the answer, which he took for mockery.
shownOne Punch Man · ch. 10, p. 14
Puts Genos into the tunnel wall, then breaks apart the left side of his face with a single punch.
shownOne Punch Man · ch. 10, pp. 9-20
Blows Genos's own fire blast back into him with his breath, ending the cyborg's part in the fight.
shownOne Punch Man · ch. 10, pp. 25-31
Senses Saitama's strength mid-charge, leaps back across the room, and says he would have died attacking.
All 7 citations
statedOne Punch Man · ch. 11
Announces he will stay in Carnage Mode and rampage until the following Saturday.
shownOne Punch Man · ch. 11, pp. 16-19
Wrecks a great deal of the combat experimentation room in Carnage Mode.
shownOne Punch Man · ch. 11, p. 21
Saitama's punch disintegrates his chest, neck and head.
shownOne Punch Man · webcomic ch. 10-11
The webcomic runs the same fight in the House of Evolution's combat chamber.
Beaten · Genos · rank 8
Demon Cyborg
Was admitted at the floor of S-class off a perfect hundred at the certification exam, and has been dismantled in itemised ways ever since: an arm off to the Deep Sea King, the left side of his face to Carnage Kabuto, an arm off to Garou — and, in a future Saitama then unwound, his core torn out by Garou as well. The damage log is the point — it is a running measurement of several other entries here. He also took a Dragon-level threat down alone.
statedOne Punch Man · ch. 16, pp. 14-16
Scores a hundred points at the certification exam and is designated S-class.
statedOne Punch Man · ch. 17
Reads the registry aloud and reports that he has been given the lowest position in S-class.
statedOne Punch Man · ch. 21, pp. 1-4
Tells Saitama he has not been moved off S-class rank 17, but is now sixth in popularity.
All 10 citations
statedOne-Punch Man Hero Encyclopedia · p. 37
Described as the first new S-class hero in two years.
shownOne Punch Man · ch. 26-27
The Deep Sea King rips his arm off, then puts him through a wall after he blocks acid aimed at a child.
shownOne Punch Man · ch. 10, p. 14
Carnage Kabuto breaks apart the left side of his face with one punch.
shownOne Punch Man · ch. 138, pp. 3-8
Neutralises one of the fusion's largest beams and melts the armour over his own core doing it.
shownOne Punch Man · ch. 83
Garou detaches his arm during their fight; the arm keeps working and slams Garou into a tree.
shownOne Punch Man · webcomic ch. 108, p. 7
Destroys the Forest King on his own, along with its army.
statedOne Punch Man · ch. 190
The manga sets the Forest King at Dragon level; the webcomic never assigns him a disaster level.
What this does not settle
One fight in one work. It is the only result the record gives between these two, and it is evidence about that meeting and nothing wider — not a general matchup, not a rematch, and not a ranking of its own.
The ladder above it is argued from everything either of them has been shown doing; this page is argued from one citation.
Where the two disagree, the disagreement is the point, and it stays visible rather than being resolved by whichever of them happens to be on this page.