I don't think it's done on wins, due to the logistical nightmare of making that happen.

Suppose the server is not too full. Suppose you just beat the only other "good" player on the server for your 11th win.
There are no other players on the server with more than 4 wins.

How long is it going to take before you have a worthy opponent?

It's no good. Players already complain about how long it takes between matches and it's less than 15 seconds in many cases.

Of course, this is all speculation.

There's another point that your opponents are always your rank +/- 1, so that places a further restriction on choosing your opponent if the server also has to match your number of wins.