The PVP match-making system is based on Level, PVP score and Team Score which affect the amount of points you earn in match-making.
It's worth noting that all wins are equal, however, some count more than others based on the PVP match-making. For example, guild and level affect points received, as well as the opponents the enemy player chooses (which may be a small, medium or higher trophy reward) and additional trophies could be earned by losing less defences.
For example, if a lower level player is on the leaderboard above you, they may be awarded more points for fighting the third opponent presented in match-making as they are a higher level and the match is deemed as significantly harder for them.
Team Score is calculated based on most of a player's overall game progress and your Team Score compared to theirs will help determine the PVP Points you receive. To learn more about Team Score see this article here.
Note: Here, the third opponent gives more points because of their higher team score.