Sleep can be annoying for low levels.

Sleep, along with chaos, can be carried onto the next round if the timing was right. Your problem is the Haze clone; it ensures SB's sleep always goes last or second-last, which could make the debuff lasts longer. It also not affected by Taunt, so rip whoever you put in front of SB.

But...

Sleep can be deflected by Genjutsu Mirror. It is dispelled if you got hit with Taijutsu moves. Or a simple cleanse could get rid of it.

Sleep is kinda good against low-level MBs who haven't unlocked their RoW yet.

A fully awaken Kurenai is good enough to counter low-level SB. Cleanse, debuff deflect and heal. Or maybe the Earth Pains team to cleanse debuffs?