Argyrosaurus vs Tyrannosaurus

Both

Assuming both are healthy adults Argyrosaurus would win 99.99+% of the time. With that much of a size difference it is just impossible that any carnivore, alive or dead, would even size up to a fully grown one-ez sauropod.

I doubt Tyrannosaurus would attempt to fight a sauropod this size, especially alone. It is not at all adapted for hunting sauropods, and it is unlikely it will have an effective way of attacking it. Carnosaurs like Allosaurus and Carcharodontosaurus attack their prey (using their jaws/teeth) in a manner which is designed to cause blood loss and damaged tissue, making them far more effective sauropod hunters as they can carefully time their attacks and deliver a blow which will be short (and leave them less exposed to attack from the sauropod) but will cause more damage over a period of time. Tyrannosaurus will not be able to do this in the same way as its jaws are designed for gripping and crushing (and killing in one go), which will be far less effective on an animal this size due to its sheer strength and durability. It is possible that Tyrannosaurus could win this fight but I see it more likely that the sauropod will crush the theropod with its bulk/legs or whip it with its tail (with a chance of knocking the theropod from its balance) when it is too reckless or unwary.