Knuckle Bine vs Serpico: who would win?

Serpico favored — Slight edge (~55%)

Knuckle Bine · Hunter x Hunter · Base

Tier
8-A, up to LOW 7-C
Attack Potency
Multi-City Block Level, up to Small Town Level
Speed
Hypersonic, up to Hypersonic+
Durability
Multi-City Block Level, up to Mountain Level+

Serpico · Berserk · With Sylph Cloak & Sword

Tier
8-A
Attack Potency
Multi-City Block Level
Speed
Massively Hypersonic
Durability
Multi-City Block Level

A heuristic estimate from normalized VS Battles Wiki stats: tier, attack potency, speed and durability.