This again.
To think mass and strength doesn't give an individual an advantage in a fight is to be completely idiotic.
Muscle doesn't make anyone a good fighter, of course, but it provides protection, and it gives movement torque and power.
Strength, skill, cardio, hunger, flexibility, co-ordination, etc. ... all attributes that help in a physical altercation. The more of these you have in your favour, the greater your chances of victory.
Please let's not talk nonsense.