I don't know what the battle power difference is... but judging by the health of you two, it looks like this is simply a case of higher battle power beating better ninjas.
Combined with your barrier and Iruka's shielding... guy really probably shouldn't win that one.

Not impressed.

And so far as your question about him being worth it? It wasn't a real question and you just wanted to post a pic of you beating Minato. Again... you were supposed to beat that Minato. I don't think you look cool for your pic here, bud. Sorry.

At least show a pic next time where it looks like an even fight next time?

But no, Minato isn't so good that he single-handedly beats everyone all the time with no regards to anything at all like difference in battle power or anything else. Minato can lose... you know, in case that wasn't actually obvious to anyone before.

Having said all that, Memorythepast could take you out with nothing but a Choji - that wouldn't mean Choji was secretly OP though; it would only mean that Memorythepast was able to take you out with nothing but a Choji.