Rudi Second scored his third hundred of the season to guide the Knights to a 113-run bonus-point victory over the Cape Cobras in Bloemfontein on Tuesday.
Second finished on 111 not out to help the Knights post a target of 279-5 after they chose to bat first.
Tshepo Moreki, who took two wickets in one over, claimed 3-45 and was the best bowler for the Cobras.
The Cobras, who have already secured a home final in the One-Day Cup, were bowled out for 166 in 42.5 overs with Malusi Siboto taking 4-32. Stiaan van Zyl top-scored with an unbeaten 70.
The Knights’ playoff hopes were long extinguished although the win saw them move off the bottom of the table and into fourth place.
With a home final already secured the Cobras were in the fortunate position of being able to rotate their team as regulars Dane Vilas (injury), Andrew Puttick (suspended), Dane Paterson (rested) and Justin Ontong (rested) were all missing from the starting XI.