One Punch Man delivered its most destructive clash when Garou transformed into Cosmic Fear Mode, wielding abilities granted by the mysterious entity called “God.” This evolution gave him control over nuclear energy, cosmic radiation, and martial arts so warped they could obliterate star systems in a single strike.
The simple answer remains unchanged: Cosmic Fear Garou cannot defeat Saitama in One Punch Man, despite attaining the most formidable transformation ever witnessed in the series. With this divine boost, Garou briefly matched Saitama’s strength through his replication powers. Even with cosmic awareness and reality manipulation at his disposal, Garou discovered that matching current strength means nothing when facing an opponent whose potential increases without limit.

Garou's transformation into Cosmic Fear Mode marked his evolution into an entity of unparalleled destruction. Upon gaining “God’s” power, Garou also grasped the flow of all energy and the mechanics of every cosmic force in existence. He can now even control the energies of the universe at will.
This cosmic awareness granted him abilities that surpassed conventional understanding of martial arts and physical combat. The Hero Hunter's new form featured a void-like appearance filled with galaxies and nebulae. His mastery over nuclear forces allowed him to unleash devastating attacks like the Gamma Ray Burst and Nuclear Fission techniques.
The battle that shook the universe of One Punch Man

The confrontation between these titans began on Earth but quickly escalated beyond planetary boundaries. Their initial clash required Blast and his interdimensional allies to redirect the energy away from Earth, preventing complete annihilation. When One and Murata first revealed the clash of two Serious Punches, Blast intervened, redirecting the immense energy and channeling it into a single path. As a result, it drilled a hole to the universe.
One Punch Man's most destructive sequence transported both fighters to Io, Jupiter's moon, where their battle could unfold without endangering Earth. His cosmic upgrade enabled him to open portals, imitate Saitama’s skills via his “Mode: Saitama” form, and unleash attacks capable of annihilating planets and beyond.
The key factor that determined the outcome was Saitama's unique characteristic within One Punch Man: his unlimited potential for growth during combat. Though Garou could duplicate Saitama’s existing strength, he failed to mirror the hero’s constant, limitless growth.
For a brief moment, Garou was able to match Saitama and therefore comprehend Saitama's level of power. However, this parity proved temporary as Saitama's emotional state and the intensity of battle triggered his limitless growth mechanism. Saitama's escalating power quickly surpassed the limits of Garou’s copying technique.
The decisive moment: time manipulation

The battle's resolution involved one of One Punch Man's most extraordinary sequences. Garou's final technique involved teaching Saitama time manipulation, allowing the hero to deliver a "Zero Punch," an attack that reversed causality itself. This paradoxical strike occurred before it was even thrown, making it impossible to dodge or counter.
The time travel sequence demonstrated that even when granted the ultimate technique by his opponent, Saitama's application exceeded Garou's own mastery. The hero's ability to utilize any power to its maximum potential reinforced his status as an unbeatable force within One Punch Man.
Cosmic Fear Garou's presence alone proved lethal to ordinary beings through cosmic radiation emission. This passive ability killed several heroes and civilians, including the young boy Tareo, whose death served as a catalyst for the battle's intensity.
The core distinction between Saitama and Cosmic Fear Garou lies in their relationship with power itself. Garou's cosmic abilities, while vast, remained finite and dependent on external sources. Saitama's power in One Punch Man operates on different principles entirely. His strength appears limitless, not because of cosmic awareness or divine enhancement, but due to an intrinsic characteristic that allows infinite growth.
While Cosmic Fear Garou achieved the closest anyone has come to matching Saitama in One Punch Man, ultimate victory remained impossible. Even divine enhancement and cosmic awareness pale in comparison to the simple yet profound concept of unlimited growth potential. Garou's defeat reinforced Saitama's position as the ultimate force within the series.