Use skills like Restart or Destiny Draw to help draw your fusion cards.
Once you fusion summon Dark Paladin, you will want to prepare some throwable cards so you can negate her Court of Justice 3 times. This will prevent her from summoning Wingweaver, which will be boosted by Freya's effect making it 3150 attack.
You might need to keep destroying her monsters so Tea doesn't tribute summon Wingweaver, unless you are sure that Tea doesn't have any Freya on the field, or in her deck.
Continue until your last turn where you will need to fusion summon another monster and normal summon Vassal with Secret Pass, and double Union Attack for the win.