Genjutsu is one of the most baisc attacks from Sasuke. Look at Sasuke's personality, he thinks he's superior to everyone, so one of his most basic attacks he'll use is genjutsu, because to him it's now a simple attack for any experinced ninja to face against, if you can't beat a genjutsu, then you're not worthy of being a match for Sasuke. He will never use Ameterasu or Susanoo in a match knowing he has a weaker attack to use against them. If you read or watch Naruto, then you should know that Sasuke always use genjutsu before any of his stronger attacks. You're actaully taking away one of his most over used abilities in exchange for his stronger attacks in oder for Goku to win.
They are not in the process of fighting until they look at each other. Which means Sasuke has the superior advantage. He'll win the fight knowing that Goku has inferior abilities under hypnosis.
Goku's very thought-processes operate at a level that Sasuke's can't begin to match.
Goku, before Sasuke can even process the thought to use a Genjutsu or even so much as look at Goku, or I don't know, activate his Sharingan because it isn't activated by default, can clear the distance and remove Sasuke's head from his shoulders.
You can't begin a battle without looking at your opponent first. It's impossible to think without looking at your opponent first. He'll be caught in the genjutsu first, then he'll begin trying to move faster than Sasuke, because he won't move unless he feels threaten. That's just one option that could easily lead to another option as well, a shadow clone. Either way, I don't see Sasuke beginning the fight without setting Goku up for a genjustu.
What you don't see is contradicting to how Sasuke has been fighting the entire time.
Sasuke vs Team 7: Straight up stomps them with tai and ninjutsu.
Sasuke vs Orochimaru: Beats him in taijutsu, only using genjutsu as a last minute tactic.
Sasuke vs Deidara: Sasuke fights him mostly with taijutsu and ninjutsu before using genjutsu to try and create an opening.
Sasuke vs Itachi: Itachi was in control of the entire fight. It's very likely he initiated the genjutsu battle.
Sasuke vs Bee: Uses genjutsu last.
Sasuke vs Kage: Doesn't try genjutsu on any of them, save for one random lackey.
Sasuke vs Danzo: Uses Susano'o and Amaterasu before Tsukuyomi.
Sasuke vs Kabuto: Well he really couldn't use Genjutsu here so whatever.
Sasuke has never shown that he considers beating genjutsu to be a sign of worth. Quite the opposite, if the opponent defeats his taijutsu and ninjutsu, he'll try and use genjutsu to create an opening. It is literally a support ability more than anything else.
You assume that Sasuke's Sharingan is on by default. This is not the case.
You assume that Sasuke can use Genjutsu without having to think to do it. This is not the case.
You assume that Sasuke can activate Sharingan, look at Goku, and then use a Genjutsu on Goku, before Goku can punch him. This is not the case.
Get the **** out of here. Goku stomps this fight by punching Sasuke, and you're deluded if you believe otherwise.
The moment the fight begins, before Sasuke can process the thought to use a Genjutsu, Goku has taken his head off of his shoulders.
Edit: Shit, even discounting all of that, Vegeta, whose will is all but definitely less than Goku's, was able to resist Babidi's mind control, taking the power it brought without being Babidi's slave. Sasuke has nothing.
Sausuke always begin the battle with Sharingan active, he'll most likely use his eye's before Goku begin to attack because this is how they both examine each other fighting ability. This is just my assumtion if you were to keep things equal, separate from the both of them having any knowlege about each other's abilites. Sasuke would most likely win because you have to see your opponent, which is what Goku will have to do in order to engage in combat with him. And Sasuke is use to fighting enemies with long range attack's, so he'll most likely use a genjutsu, if Goku understands the counter to his eye technique, then he'll move on to to another attack. Take a look at Sasuke's fight's, since he learned genjutsu, his opponenet was already prepared to counter his eye technique's, that's why it wasn't a problem for them. Goku doesn't have that benefit of knowing about Sasuke's genjutsu so he'll most likely get caught.
Remeber Itachi's fight with Deidara, he was completely dominated by one of Itachi's most basic moves because he had know knowledge of what he was facing. What do you think Goku is going to do when he see's Sasuke's eye's change, nothing, because it means he's probably already under hypnosis. Remeber the fight with B. and Madara, he couldn't believe he got caught in one of the most basic eye technique's and it happened instantly, this just prove that character's with knowledge of the eye technique are still inferior to an someone like Sasuke. Sasuke wins this from a distance, it's just impossible for a Sharingan user to begin combat without using a genjutsu IMO.
Well your opinion means nothing compared to the manga that says otherwise. Sasuke, Kakashi, Tobi, and Madara all fight without starting with a genjutsu. Itachi is the only Uchiha that uses it like that and even then, he can start a fight without using genjustu.
Look, I get it. For debators it's hard to think in terms of character rather than the easiest possible route to victory. I don't believe Goku would literally punch Sasuke's head off. Goku isn't that vicious. He'll knock him out, on accident probably, but not kill him. He can tell that Sasuke is no match for him.
You just ignored that Sasuke could hypnotize him again, since Goku again have to look at his oppnent to hit him. And Sasuke alway's begin a fight with Sharingan activated.
Dude, Sasuke doesn't fight that way. He just doesn't. If you wanted the fight to hypothetically go that way, you should have made it Itachi instead. Hell, he's stronger anyway. As it stands, Sasuke will probably start the fight by opening Susano'o or trying to attack Goku with his sword.
Sasuke can actually take a hit and if serious, he'll use the genjutsu first. It goes against logical reasoning to think that Goku stands a fair chance of beating Sasuke without being hypnotize.
Sasuke didn't hypnotize the Raikage and Goku is far above A in both speed and strength. And he has never used genjutsu first thing in a battle(outside the battle Itachi started). If you can prove me wrong, then do it and I'll consider the possibility of Sasuke catching Goku in a genjutsu off the bat(Goku would win either way though so not like it matters).
Raigkage knows how to counter genjutsu, Goku doesn't, so he'll be under hypnosis as soon as the fight begins. Speed or stregnth is not an issue because Sasuke won't be fighting with Goku since the match will be over once he's under hypnosis.