Mech Mage, now with more Burn! When the minions aren't enough, face damage from Fireball, Explosive Runes, and/or Pyroblast off the top-end should finish the job. Combined with the pings from Mecha-Shark and Gaia, the Techtonic, you should be able to reach for lethal.

If there was more room in the deck, I would consider Sanctum Chandler, Hot Streak, and maybe even play Grand Magus Antonidas...nah, probably not that last one lol.