How are win odds calculated? | Test Your Might

It’s baffling me you would feel that it’s calculated using the amount of wins a participant has, their win/loss ratio or both yet I’m considering a single man with 1649 wins and 613 losses that I seemingly have a 72% chance of beating, and yet another man with 380 wins to 260 losses I apparently have an 18% chance of beating. It does not seem to make any sense.
Unless, obviously, it is calculated by factoring at the stats of every player you have beaten/lost to, but that sounds a bit overly intricate.
Am I missing something obvious or are those win odds percentages?
EDIT:
For those looking for the response, the overall (unconfirmed) consensus is that it is calculated with a method very similar to the Elo rating system that calculates skill based on who you fight e.g. you will have more skill points beating good players and lose less losing to great players and vice versa.
EDIT #2:
It is certainly an Elo-based points system; I have just noticed there’s a”Score” column to the player game leaderboard so these points must be given/removed dependent on how many your opponent has.

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