Ranked matches are not only one match, they are a best two out of three three out of five every time!
Also keep note that you will not be able to decline the first opponent you find, so you'll be forced to fight that person every time. Boosting this is hard, I'd recommend you both search at the same exact time, and hope you find each other. However if you don't find each other, you won't be able to quit without the game giving you a penalty (don't remember what happens).
EDIT: It's been brought to my attention by Kerman7 that ranked sets are out of five and not out of three. Also you may sometimes be able to decline some opponents