Allosaurus VS Tyrannosaurus

Two Allosaurus mob a Tyrannosaurus who has intruded into their territory.
Though no single Allosaur could fight a T-Rex and win, A pair might be enough to fend off the tyrant king.

(Note T-Rex and Allosaurus are both from north america but did not live at the same time. this confrontation could only take place someplace like Jurassic Park.)