Is my rabbit safe around squirrels?

First time bunny owner who got him roughly two months back. I let him out in the backyard when the weather's clear, but today I come around to see a squirrel on the back porch staring Waffles down, a few feet away from him.

I of course charged out and frightened the invader off, but I'm worried about the future of these interactions.

Is it safe for my rabbit to be around squirrels or should I stand guard every time he's outside?