The achievement states win 100 online matches. I've won 192 matches and this achievement hasn't unlocked for me. Do you have to win 100 in either player or ranked matches or does it count the sum of them?
Its odd, certain wins don't count (such as disconnects and player quits) so I've heard. If you keep winning you should get it sooner or later.
My wins came from player matches, single not tag. Not sure if it matters or not but thought I should include thatr :P.
Not ten minutes after I posted this did I win a gmae of KoTH and it pop up haha
Haha nice, grats.