Rilee Rossouw and Dean Elgar combined in an unbeaten century stand, guiding the Knights to a comfortable nine-wicket victory over the Dolphins in Bloemfontein on Wednesday night.
The Dolphins were restricted to 131 for five after they won the toss and chose to bat, and Rossouw and Elgar shared 127 runs for the second wicket, carrying the hosts to 133 for one as the Knights stayed in the race for the Ram Slam T20 Challenge title.
The Dolphins remained bottom of the table without a win in five matches in the competition.
Rossouw made 61 off 47 balls and Elgar contributed 61 from 43 deliveries after opener Loots Bosman had been removed by Prenelan Subrayen in the first over of the innngs.
Chasing 132 runs to win, the home side reached their target with 27 balls to spare.
Earlier, Dolphins opener Khayelihle Zondo made 43 runs to anchor the visiting team's innings.
Zondo shared 46 runs for the first wicket with Jonathan Vandiar, who hit 18 runs.
After the pair were dismissed, Vaughn van Jaarsveld made a lone attempt to boost the run-rate, contributing 39 off 29 balls, but the Dolphins were well restricted by the home side's bowling line-up.
Seamer Johan van der Wath took two for 29 to spearhead the attack, preventing the visitors from building solid partnerships, and providing the hosts with a reachable target.