tbh hiruzen has no chance against minato... hes too op cuz of his s/t techs . rasengan and his sealing jutsus.. and what does we know abt the old man.. low chakra reserves . weak summoning. a few jutsus in his arsenal.. maybe prime hiruzen culd have stood a chance again against minato but i dont think so actually.. :dunno:
You DO have to remember that Hiruzen was displayed in Part 1, where the power scale was MUCH different. Average Genin were as strong as kage in terms of Shippuden's power scale when looking back on it. On top of that, Hiruzen was an old man and WELL into the age where he shouldn't have even been fighting anymore, yet he took on an immortal Hashirama AND Tobirama (argue all you want, the two of them were NEARLY at full power. Not at absolute full power, but damn close) with unlimited chakra and stood his ground VERY well.
Now we can't say for SURE how powerful Hiruzen is as of now or as of his prime. He WAS hailed as the Professor of all Ninjutsu AND formerly the God of Shinobi (until Hashi pretty much ripped it off). In this case, his matchup with Minato can't really be foretold. And with Minato now having the Nint Tails Chakra, it really is a toss up.
Basically, what Daisy is saying to you is that you aught not underestimate Old Man Sarutobi.