Heh, this sounds kinda dumb, but I won it with Suchotator (lvl 14) and Postimetrodon (lvl 16) and used Ankylocodon (lvl 15) for finishing off. Used Lethal Wound the first move, because my opponent always used Rampage first with the Alanqa. Then I used Nullifying Impact, because of the typical swap, and then Instant Cripple so I had more health after a Rampage or another high-damage move. Worked perfectly, and the rewards are definitely worth it! Can already unlock Alanqa, and got 75 DNA of Pteranadon. Try things with high health and DoT moves, because of the high health and all the Invincibility moves.