Congrats on your new pet !!! I would just make sure to watch them closely & NEVER leave them alone together. Most big dogs I've known have been laid back (As if, "Yep, I'm a big dog, I've got nothing to prove"), but it's the little ones that have the attitude/are fearless.
I used to have a greyhound, and she was as gentle & protective as could be with my wife's Yorkie, my mother's Chihuahua, other small dogs, cats, etc. Evidently, with the size difference it was apparent who was "alpha dog" (that & the big, lowdown I've-had-enough-of-your-nonsense-growl
), as previously mentioned.
Good luck with your new pet !!!