The sannin probably win this under these conditions. This is a perfect team who spent a ninja world war fighting as a team and presumably spent decades together with full knowledge. As soon as the fight starts a Rashomon Gate is thrown up to avoid Amateratsu blitzes and to block LOS. Directly afterwards Jiraiya uses shadow clone jutsu to create three clones. Shadow Clone J-man one uses Yomi Numa under Sasuke meanwhile shadow clone 2 summons Gamabunta underneath the sannin. To counteract Yomi Numa, Sasuke may aim a fireball downwards to quick dry the ground. All the while Tsunade uses Food Cart Destroyer with 1% Katsuyu then restores her teams reserves; Orochimaru creates three Shadow Clones and summons boss snakes to circle back from behind and below Sasuke.
Shadow Jman clone one remains behind Orochimaru on Gamabunta using Yomi Numa as necessary. Meanwhile Oro Shadowclone 1 has Rashomon on standby. Meanwhile Jiraiya starts prepping Sage Mode.
There's only one way to avoid a K.O. at this juncture. And that's moving across the x and y axis as the z axis is perilous. If he moves forward he's leaping into Goemon Sannin style. With a Tsunade enhanced Toad Oil Flame Bullet and an Enhanced Great Wind Release Breakthrough. If he moves backwards he's greeted by Boss Snakes above and below ground pushing him toward the Swamp or the Goemon. His movement side to side would be restricted by the emergence of the other two goemon gates on either side of him. As Shadow Clones 2& 3 flank from both sides of the goemon gates where LOS is restricted. Susanoo won't be used because to avoid the massive size of the Swamp he'd need to move quickly and the swamp would sink his susanoo.
It's possible Sasuke may survive that initial onslaught by using Amateratsu on the boss snakes. But that only gets him so far because more snakes are underground. And if he deals with those promptly at that point a second swamp is used where he is going to land.
The sannin can stop this fight from being mid to close range until they are ready to use Frog Demonic Illusion Chant. But since I've just argued that Shadowclones 2 & 3 would be engaging in Mid to Close combat in tandem with the summons let's address that. This is hardly part 1 Jiraiya or Orochimaru. Especially considering that Orochimaru now has Hashirama cells which increases his chakra pool, strengthens his jutsus, and grants him the mokuton. Abilities that his Shadow Clones will also be able to utilize.
Oro Shadow Clone 2 uses Hiding like a mole technique to approach while Jiraiya Shadow Clone 2 drops Gamaken on Sasuke. Upon reaching Sasuke's location Oro Shadow Clone 2. Uses Formation of 10,000 snakes as a diversion and sends many shadow snake hands Through the swarm to grab Sasuke.
Jiraiya shadow clone 3 uses shadow clone jutsu and Transparent Escape Technique before emerging into Sasuke's LoS. Jiraiya shadow clone 2 uses Wild Lion's Mane then Toad Oil Bullet. Orochimaru shadow clone 3 uses his mokuton jutsu. Orochimaru shadow clone 2 uses Wind Release: Great Breakthough. Meanwhile Jiraiya shadow clone 4 uses Fire Style: Flame Bomb. Jiraiya shadow clone 3 sneaks up on Sasuke using the elemental blasts to hide his chakra and the further diversions created by gamaken, and proceeds to use Toad Flatness - Shadow Manipulation Technique to hold Sasuke. Gamaken jumps in the air to smash Sasuke with his weapon. Orochimaru shadow clone 3 sends Longsword of the Sky to pierce Sasuke's heart from the side. Sasuke's only defense is susanoo. The instant he uses it Jiraiya shadow clone 1 throws out another Dark Swamp sinking Susanoo. Gamabunta shoots Water Release Gunshot from the front. Gamaken's weapon lands from above and Goemon bakes from the back. Orochimaru shadow clone two uses another Mokuton coupled with a fuuton.
I'm not really sure how Sasuke avoids this but assuming somehow he manages to escape this all of this should have bought enough time to have everything prepped.
The only option left for Sasuke is Kirin. Assuming he found the time to prep it before, which is a major assertion but not completely out of the question. The sannin respond by Jiraiya using a Dark Swamp to sink the sannin themselves. Mud is a great insulator and given the depth of the jutsu should save the sannin. Orochimaru uses his hiding like a mole technique to grab the other sannin from below ground. Demonic Illusion Chant should be ready to go and Jiraiya casts it behind a Rashomon gate Orochimaru sets up. Orochimaru then charges forward and Tsunade charge forward. Orochimaru Summons Manda to attack from below then creates Mokuton structures to provide himself cover as he uses slither snake form to charge towards Sasuke. Upon reaching Sasuke he uses 8 branches technique. Tsunade is still almost complete unknown to Sasuke and thus has no clue what to expect. She advances from the other side to Jiraiya shadow clone 2 another Rashomon Gate courtesy of Orochimaru Shadow Clone 1. She summons another Katsuyu and has her divide up. And use a multi directional acid attack. Sasuke probably dodges but can't kill Katsuyu by normal means and can't kill her all at once with Amateratsu. Frog Demonic Illusion Chant catches. Many Katsuyu's individuals melt into a reverse healing pad beneath Sasuke and Byakugou Tsunade slams Sasuke with a punch. Or he gets nailed by 8 branches. Or a Katsuyu mini melts him. Or Jiraiya stabs him with his stone sword. Or Big Ball Sage Enhanced Rasengan.