This is the ultimate argument by definition. Define a great power as anybody that scores at least a minor or temporary strategic victory against another great power. Toss out all the other definitions because I don't like them. Then, posit that Iran just had this kind of victory. Ergo, Iran is a great power.

Except this is not a commonly accepted definition of a Great Power. I'm not sure there is such a magical Platonic definition. The concept has been contested by many scholars. Kenneth Waltz had a more holistic conception focused on a state's aggregate capabilities. Mearsheimer had something closer to what you're talking about. Keohane had a more institutional angle. Others have their own takes. You claim this is how history has always been (but nevermind evidence since you don't have any). Tell me, do you think Haiti became a Great Power after outright defeating the French in 1803 and gaining independence as a result? Your position leads to ridiculous conclusions. Who cares about the European balance of power when we're talking about the United States and the Middle East? Yes, a country can score a temporary victory against a more powerful country (even a Great Power), that happens often in history actually. That doesn't always elevate the winning underdog to the status of a Great Power. Sometimes it does, sometimes it doesn't. History is more complicated than how you portray it here. For example, sometimes defeating a Great Power, like in the case of Haiti, actually results in isolation from the international community, and thus the loss of any seat at the table, any ability to shape rules and institutions governing the global order.