Kong
Spinosaurus in JP was wrongly depicted. They may be bigger than T-rexes but the general concensus is that they eat fish or something smaller (hence, the long snout). And they aren't as massive as a T-rex.
In any case, even if Spinosaurus was that powerful as shown in JP3, Kong can beat 1 since he beat 3 V-rexes, which should be able to take down 1 Spinosaurus.