The underdog has nothing to lose. If they win that's great, if not then they weren't ever suppose to be there anyway.
The underdog has a relentless pursuit. They have nothing to go back to so they don;t give up - they "go big or go home".
The underdog has to believe for the miracle. All the odds, stats, & favors are against them & when no one else believes it they do.
The underdog is always described as having much/great heart, and that's what does it. The heart of an underdog captures attention and creates a buzz. & its the heart that God looks at (1 Samuel 16:7).
The bible is full of underdogs who God lead to greatness, but it wasn't just then, God still uses underdogs today! (I Corinthians 1:25-28)
The underdog is always a threat because he plays with everything in him!