An advantageous perceptive can only be attained by individuals with substantial intelligence/a strategic mindset.
Course I;
Zabuza conjures Hidden Mist - Shikamaru through adaptable intelligence erects a several meter wide circular shadow around himself -- His body's natural shadow being the vessel for conjuration.
Zabuza is incapable of seeing through the mist, only through smell, and sound can interaction become noted -- In every case, Shikamaru's shadow have been shown to be silent (clearly).
-Zabuza attempts a swift decapitation
-Shikamaru's shadow restrains Zabuza
-Shikamaru utilizes the shadow to perform Kage Nui no Jutsu -- Binding Zabuza
-Shikamaru combines prior technique, and uses Kage–Kubishibari no Jutsu -- Suffocating Zabuza, or utilizes a simple kunai to the brain tactic
-Zabuza dies
Q; How does Shikamaru know where to strike via kunai?
A; Connection with chakra allows indirect sensory -- If x is connected to y's chakra in close proximity, than y will know of x's location (i.e. Shikamaru will know of Zabuza's location once he's in contact with his shadow chakra).
Shikamaru clinically murders Zabuza.
Food for thought;
Shikamaru dodged Kakuzu's elemental assault -- Are Zabuza's water ninjutsu faster than Kakuzu's? Asinine question clearly -- If Shikamaru is capable of evading an Akatsuki member's ninjutsu, I find it foolish to believe he'd not evade a lesser.
Food for thought II;
Expecting Zabuza to not act instinctively as he's done several times canonically (i.e. mist -> assassination) -- Zabuza acts on instinct similar to how he's done prior -- Zabuza trapped in Kagemane -- Zabuza dead. Simplistic.