Lilac, absolutely! Wonderful question. :-) The underdog story’s how goes like this:

1. You create a situation of big guy vs little guy.
2. You embrace being the little guy putting in way more effort than is expected of you.
3. It is important to show all the times the little guy tried to win. Even if things didn’t work out. The more effort you show for the little guy, the more empathy the reader will have towards him/her and ultimately pick his/her side.

When to use it:

In any situation where you or your brand is outgunned by a competitor. In a situation where chances are you won’t succeed.