Garra can bury him in any dirt,not just the desert. Has everyone forgotten how he nearly crushed kimmimaro? Had it not been for his kkg he would have been fodderized. I say it'll be one hell of a match,a lot of variables to consider here. Neither commbatant is to be taken lightly.
But to answer your exact question, no kisame will not "solo" as you so eliquently put it. Who ever wins will have to work for it.
Kisame can drown Gaara in water, but Gaara can drown him in sand. If Kisame is stuck in sand he can make water, and if Gaara is stuck in water, he can bring up sand. Just... Don't think about it too much, too much, too much, too much...
I think Gaara is stronger, but Kisame is a bad match up and both are on the same tier. But I doubt Kisame can absorb sand with samehada. I have no idea actually. But, I'll go with Kisame.