>>63960175
A very large bull elephant might stand a chance, but honestly my money would be on the Tyrannosaurus. Average sizes for adult Tyrannosaurs seem to be pretty well in-excess for the average sizes of elephants. Elephant tusks aren't really in a good position for use as weapons, and an elephant would have no experience with a predator larger and stronger than it while a Tyrannosaur habitually went after prey as large as itself. I think given some of the bite force calculations, if a Tyrannosaur got a bite in, it would be all over.