This isn't really a solution for any particular achievement, but I'm going to post this because I had a hell of a time trying to connect to my friend after we played one ranked match, we searched and searched but could never find each other to boost the rest of the ranked stuff. I finally stumbled onto the solution to this problem on a website online, and I'd like to offer this tip.
If you were like me and my friend you'll want to change the ranked match to more than 2 people because the game developers did not want players playing ranked against each other more than once in a row, change it to 3 or more and your friend should be able to find your game to boost.
Hope this helps someone having the same problem that we had.
Remember to upvote if you found this helpful, thanks!