It IS the correct fitting, but you need to make another cut above, and then a new properly sized piece of pipe with a banded coupling at either end to insert and take up the gap. Done that way, you can seat the fitting right to the stop on all ends. I wouldn't want a 1.5" gap between the ends of the pipe in there. See what one of the pros think, but it's a simple fix...cut say 6" off of the pipe above. Get another fitting. Cut a new piece of pipe so that it is just short enough so that when bottomed out in each fitting, it would just fit in between, tighten them both down, and sleep well.
The alternative, I'd mentioned, would be to have used a repair coupling, but unless you use them a lot, it's an art to getting a good seal. A repair coupling has no stop in the middle, so you slide it up one way, insert the pipe, then slide it back down. Hassle is, once you put the cement on, you have almost no time, and especially on a larger pipe, it's tough to move. Until you get the knack, you're likely to only be able to slide it back a very short amount, if at all, and then you won't have a very strong connection. With that, timing is everything, and practice definitely helps. It's too late for that now, and IMHO, on a first time basis, probably wouldn't have worked anyways.