If not for the anime, I would have said Kakashi vs Obito. But the anime completely did that fight justice.
One fight I wish was extended and made a lot better is Minato vs Ay and Bee. Or at least have shown one of their rematches.
I still beleave that Minato was the best ninja. Ay said that MInato knew the Uzumaki tecnics, but if you anylize you will see tat Minato had a lot more tecnic because the the shikun fujin he couldnt use it against him, the contract seal neither, the 4 simbols neither, the one hand seal neither or bee would be dead, the 8 tritigram neither, so if Ay says that Minato learned the Uzumaki tecnica he must have see him use them, but in the first fight he didnt, so the other tecnics must have been offensive tecnics to make him think he was not possible to surpass.
What did Ay see? What tecnics did he see? What did Minato do to make Bee tremble by listening his name? Because in the first fight he was vey confident.
I still beleave he could beat Hashirama and a lot of people. He was very strong, he is far above Hashirama in my opinion, and not in raw power, but for his tecnic with great effects. Imagine if he had a fuinjutsu to make you lose control of your chakra like the 5 elements by one touch like the contract seal, then with that he could manege to weak Hashirama, the Hashirama would go to a deep sleep like Naruto did when Orochimaru put him the seal.
Or imagen that he could put on him a seal for antigenjutsu ocular tecnics. It is posible.
He master in my opinion the best area of all the tecnic, the fuinjutsu and also manege to make some of himself. The contract seal is a tecnic he develop because it is not a Uzumaki tecnic and you can see it in the formula of the seal, there is no whirlpool formula in it.
He develope the hiraishin formula from his knowledge in the fuinjutsus, he did not just copy Tobirama jutsu, that is wht Minato seals can sense and Tobirama cant. That is why Minato could make his barrier from the formula. And a lot of things.