I know old school RS has this, but simply have a tracker in the chat box after every time you win or lose a duel!
Here's the example:
I win a duel, in the chat box it shows
"You have won 1 duel(s), you have lost 0 duel(s), you have tied 0 duel(s)"
*You cannot tie a duel in OSRS since they use a pid "First hit" system but we have ties on Alora.
Rather simple suggestion, but would always be fun to compare wins with your friends or things like that! Let me know what you guys think, could also be cool to see if you're a staker and want to keep track of your wins compared to losses.