If Two Strength-13 Fighters Arm-Wrestle, Which One Wins?

Is there a D&D mechanic to simulate this sort of contest, or would each of you simply roll a d6, high number wins?

What about if a Stength 14 fighter arm-wrestled a Strength 13 fighter? Would the Strength 14 fighter win every contest?

I ask because Dying Earth RPG has an interesting dice-pool mechanic, where your attribute score is the number of dice you receive. Potentially, in that circumstance, a lower strength character could beat a higher strength character, if the former was lucky or the later unlucky.