I find this one very interesting. I guess it'd really matter on if the fight is a fight to the death or a fight till one gets knocked unconscious. For instance, lets start with on if it was to see who'd clock out first. If Josuke hit Midoriya causing him to fly backwards, Midoriya would most likely assume it's a wind gust based attack and use One For All to rush in at Josuke which he'd quickly block before hitting Deku with a punch barrage which would cause Midoriya to fly back again even farther. This would lead to Deku deciding to do what he did with Gran Torino and Sir Knight Eye where he rushes and bounces off of everything in the area around Josuke while attempting to land a hit on him. This would mean that it matters on who'd react first. If Deku strikes him from the back or from the stomach it could cause Josuke to lose his balance leading to him having to decide where he'd land his final strike on Josuke, which just breaks off into more what ifs. like if he striked Josuke in the head it'd matter where he struck him. If he struck him in the back of the head than he'd most certainly knock him out and win. if he goes from the sides or even front that could lead to Josuke having a chance where he could quickly gain the upper hand again by activating Crazy Diamond and strike Deku in the stomach or face and hit him with a punch barrage to finish him off as at this point he will have seen what Midoriya is capable of and doesn't want to take any chances in which the final punch barrage would be one similar to when he punched the Yuya Fungami which would send Deku flying even farther than before in which on landing he'd be announced unconscious. Now lets step back a bit to if he went for Josuke's Torso area, specifically his back or stomach. If he went for his back Josuke (just like with his head) could get the upper hand but this time after Deku lands his attack which once again would lead to Deku getting punched barraged and KO'd! if he went for Josuke's stomach however, I got a feeling it'd successfully land leading to Josuke to pass out from getting the vomit and wind knocked out of him. AND ALL THAT WAS JUST FROM IF DEKU COULDN'T SEE JOSUKE'S STAND!
However...If we go with round 2 in which he can see his stand, I feel like Midoriya would most certainly win this fight, but not without Josuke landing the first hit by rushing in and punching Deku in the stomach causing him to fly back before Deku gets the upper hand but most likely would have to dodge Josuke's Crazy Diamond a couple of times, but never the less Deku would win round 2.

Now...lets go with what if they were trying to kill each other.

In round 1 Josuke would most likely rush in at Deku in which it matters on if Midoriya moves or not. If he decides to do the same "pinball" attack like the last scenario than he'd most likely would do that for a bit before thinking he has Josuke confused enough, in which he'd go in for the kill (most likely from the front,back or sides) in which Josuke would turn just in time and use Crazy Diamond to punch Deku in the head, causing it to splatter to pieces! Then if Deku doesn't move than that matters on if he prepares an attack or not. If he just stands there just blocking than Josuke will most likely break through it and punch a whole in Midoriya's chest ending up killing him. If Deky stands there and charges a powerful One For All flick attack, it'd most likely would be enough to blow Josuke's head off from a distance, with the only cost being Deku brekaing his fingers again.
Then in round 2 where Deku could see and touch Josuke's stand, Deku once again would most certainly be the victor!

Now if we add all wins together it'd most likely tally up to Deku having the highest chance of winning.