I just ulted an enemy Nautilus as Azir and it only knocked him up.

I dashed over a wall and the enemy Nautilus flashed over to chase me. I ulted him and proceeded to run. Next thing I knew, he was ontop of me and I was dead. I just watched the replay and all the damn ult did was knock him up. It didn't push him back and leave him on the other side so that I could escape. Kinda pissed me off after getting shit on in lane by a Fizz that couldn't even CS.