Imagine that Mace and his pals walk into the Chancellor's office to confront him, but find a different Sith Lord waiting for them.
Round 1: Darth Plagueis
Round 2: Darth Krayt
Round 3: Anakin already turned to the Dark Side (assume Knightfall levels)
Round 4: Sarasu Taalon (Amped by Pool of Knowledge)
Bonus Round: Lord Nyax in the conditions he fought NJO Luke under