A piece of advice, from what I have found is the shadow challenges do not count towards this, so you can only earn this by doing the 1 challenge each day from doing a fight in shadow lords, and the 4 SL multiplayer challenges, which are always 5 fights, 1 win.
However, a neat trick I have found is you can fight yourself if you have a second account and windows 10. If you use your main account on the PC, the second account will get gold on your console through your main account. Simply then beat yourself up 5 times and there is your free 5 challenges daily. 10 days and you're done.
This technique can also net pretty much all the achievements for fighting a friend and the other online ones for each character so enjoy.