Sorry guys - that popup message was due to the images in my sig (seems Heresy-Online has gone on the blink). I've removed the offending images so shouldn't happen anymore.
Awesome! Then I'm the trope namer for this.
Hmmm, well my post was actually intended to suggest the opposite of that, namely that the broader Tournament Arc trope already covers your example (and even has a paragraph which more directly relates to it which is why I quoted it) - your example is essentially a Tournament Arc with a final battle involving The Rival/Big Bad/Dragon/whoever-the-final-opponent-is at the end. All you're doing is taking that specific circumstance and trying to spin another trope off of it.
But hey, if you feel strong enough about it whack it up on TV Tropes and see what happens.
"Bea is dead. In an alternate future she would have borne your son. In the future past of Space Quest IV
, your son would've saved your life. But she didn't, so he couldn't -- therefore you aren't."
- Space Quest V death scene
Avatar by Teutonic Knight