Summon Ojama Knight or Ojama King as early as possible. They have enough defense to stall Mai's strongest monsters and with 0 attack Mai cannot use Amazoness Fighting Spirit to boost her attack.
After that just keep stalling until you deck out. Ojama Blue and Jar of Greed helps you get Ojamas out of your deck, King of the Swamp helps you search Polymerization in your deck. You can also use these cards to help fusion summon Ojama Knight earlier, if you have not yet.
I used the Ojama deck with labyrinth builder. The problems I faces before this skill change was that restart is now needed and so if you don't get what you need, it's gonna be tough. However with the labyrinth skill you're just recycling the cards and can stall until you get them back.
Sylvans with Ra. Yami Merricks "Power of the tributed" ability.
Stall until last cards in deck and then summon Ra + activate effect to have over 10,000 attack if you don't take any damage which is ez with Sylvans high attack units. Clear her field throughout the fight so she can't tribute summon.