>>166768359Once you get a decent combo on Slash and he jumps away, he always lands with his back towards you. Hit him just before he lands (auto-rush attack works well here), and he'll be stunned for a couple more hits. I'd always get him in a loop of shoulder rushes for the first several hits.
When he does that invincible-ball charge, jump to the side (or over him) and try to hit him after he bounces off the screen edge (he ought to be facing backwards again). Rinse and repeat.