Sapphire vs Undodog: who would win?

Undodog favored — Slight edge (~55%)

Sapphire · Steven Universe · Base

Tier

8-A, up to LOW 7-B

Attack Potency

Multi-City Block Level, up to Small City Level

Speed

Relativistic

Durability

Multi-City Block Level

Undodog · Super Mario Bros · Base

Tier

LOW 7-C

Attack Potency

Small Town Level

Speed

Unknown

Durability

Unknown

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