While no lion/lion cub, our big dumb black lab loves to play tug of war.
He'll pull my Wife, My Mother and certainly the kids around all day long. While he doesn't win vs. me, I still have to put some effort in. So yea, I can see this lion cub being strong.
I will throw another caveat in besides the angle of the rope and resistance being pulled through the gate... The way the lion's (cats and dogs also) legs hinge vs. ours in terms of putting power down. Ours will eventually buckle.