He was hiding in the trees, and spotted her movement off to his right, edging around the tree to make sure she didn't see him. He didn't use Genjutsu to do it, just stealth, intent and focused as he used hands and knees to scale the tree, feeding enough chakra to climb and using the tree to keep her from seeing him, plastering his body against it as he worked out the best way to get to her without being spotted.

That had always been his best skill with ambush warfare, and he moved with careful stealth from three to tree, picking his way toward her, forgoing the use of his hands for seals as he got near enough to carefully move through one of the lone water jutsu he had the precision with to slam her with it from behind and hopefully knock her out of the tree.