I'm at lvl 57 currently, the rewards are still the same. With keys, golds and SR jewel as rewards and gems when you complete the mission at stage 57. The only difficult thing here is to beat Mai lvl 40 3x consistently. As in 3 straight wins with no losses. and Mai is hard to beat at level 40.
When you are about to lose the duel, quit the app and quit the duel in progress. This way you can keep your winning streak. I past that with this trick long ago, hope it still works.
Anoymous
Hope this helps
