TIL in 1818, an Englishman accused of murder demanded a trial by combat. Surprisingly, the law that allowed for trial by combat was still valid, and the man was acquitted when his accuser declined the offer of battle. Trial by combat was abolished the following year.
No, much like the ‘trial by ordeal’, in more religious times it was believed that god(s) would grant favour to those who were truly righteous and/or innocent, allowing them to survive an ordeal or win a fight.
It was effectively a verdict rendered by god, rather than the courts.