VS
Allosaurus Fragilis: https://en.m.wikipedia.org/wiki/Allosaurus
Rules:
Stats: Male Mammut; Female Allosaurus; retreat allowed.
Battleground: North American grassland.
Verdict: I think such a battle could go either way. The Allosaurus has speed and agility on her side, and if she lands some bites with those jaws of hers the pachyderm is not gonna be enjoying life. However, the Mammut has two formidable tusks that could easily gore a fatal injury to the dinosaur, as well as tough skin that will allow him to live longer than most prey items an Allosaurus hunts. If the Mastodon charges and displays those risks enough, the dinosaur might eventually decide it’s not worth risking injury over, and bug out and call it even.
Overall, I’m leaning the Mastodon.