New Zealand wasted a promising start to close the first day of the second Test against South Africa at 187-8.
Craig Cumming and Lou Vincent shared a 62-run, second-wicket partnership as the Black Caps overcame the early loss of Michael Papps (9) to reach lunch in good shape at 84-1.
But Vincent's departure for 33 was the start of a sorry procession from New Zealand's middle-order, in keeping with their struggles during last week's first Test defeat.
Cumming retired hurt on 48 after being hit on the head by a Dale Steyn bouncer that struck between the grille and peak of his helmet - he left the field at Centurion with a deep cut to his cheek and did not return.
The 32-year-old is unlikely to take any further part in the match after hospital checks revealed a fractured cheekbone.
Number four Stephen Fleming chanced his arm while making 43 from 57 balls, but was given no support as Steyn (4-42) and Andre Nel (2-42) made regular breakthroughs.
Scott Styris (3) lasted just eight balls before being trapped in front by the pacy Steyn, and Nel had Ross Taylor (17) caught by Ashwell Prince to reduce New Zealand to 147-4.
That became 165-5 when Fleming sliced an expansive stroke straight to Prince at backward point to become Jacques Kallis' (1-35) solitary wicket.
Brendon McCullum (13) was caught in the slips from Nel's final delivery before tea to complete a miserable session for the tourists.
Steyn, who claimed a match-haul of 10-93 in the first Test, removed Mark Gillespie and Iain O'Brien for ducks with successive deliveries to ram home the Proteas' advantage under darkening skies.
Last man Chris Martin joined his skipper Daniel Vettori (16no) and survived the hat-trick delivery. One ball later the batsmen gratefully accepted an offer of bad light.
With the conditions failing to improve that was the last action of a day which featured just 56 overs.