The former England skipper and batting star slammed an unbeaten 115 for Durban franchise Dolphins last Wednesday followed by an undefeated 100 two days ago.
South Africa-born Pietersen was caught by Warriors' Basheeru-Deen Walters off the bowling of Colin Ackermann at Kingsmead Stadium after a knock including six fours and four sixes.
It was the fourth appearance for Dolphins in eight days by the T20 batsman-for-hire, who came to South Africa from the Caribbean and will play in the Australian Big Bash League this month.
An outspoken cricketer who often clashed with officials and team-mates, Pietersen last played for England on a 2013-2014 tour of Australia.