Nortje was lucky not to suffer serious injury on Tuesday afternoon when the wire-guided camera, which hovers above the players, went too low and collected the paceman from behind as he was walking to his place in the field between South African overs.
Side-on footage showed the camera hitting Nortje to his upper body at some pace, while the spider cam view itself revealed a sharp jolt with the impact.
He was knocked to the ground but was on his feet immediately and did not leave the MCG.
While the incident was only caught on replay, Australian batsman Steve Smith saw it at the time and was concerned enough to check that Nortje was okay.
The bizarre incident happened moments after Nortje's awesome post-lunch exhibition of pace bowling on day two of the Boxing Day Test.
The four-over spell conceded 11 runs and deserved at least a couple of wickets.
There were a couple of near-misses for Smith and David Warner, who needed treatment after one Nortje thunderbolt jammed a finger against the bat handle.
It was telling that Warner did not bring up his century until Nortje's spell was over.
Nortje's deliveries in the spell routinely clocked more than 150km/h and peaked at 155.
The South African paceman was true to his word, after saying in a pre-match media conference their attack would ask questions of the Australian top order.
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