There was no reason for him to throw his leg out like that, it wasn't a natural reaction during a fall to rescue himself, he'd already landed and realised he almost landed on the player, so he automatically turns away from the player, but then kicks out. It was petulant and unwarranted and he'll probably get away with it because he's not playing in a Liverpool shirt.
Accidental my arse. It couldn't be any more obvious.