Simply enter into the match type and finish it through. At the end of the match, you'll receive your achievement. There's a small group of players that still play regularly, so see if you can get into one of their games. Just search every once in a while until you get a match. Alternatively, you can get your boosting partner and play a quick Tag Match. In place of the two empty slots you need so you can play, you can instead use CPU's to play. Playing on Tag Match should also count toward "Player Match Debut".