Johannesburg - The Cobras secured a safe passage into the Ram Slam T20 final and with it a place in the Champions League T20 as they beat the Knights by eight runs in their clash in Bloemfontein on Sunday.
With the win, the Cobras ensured they could not be caught at the summit of the log with one round of matches remaining before the knockout stages.
The Cobras moved to 33 points and win the right to host the final, while the Knights remained on 22 points.
The two finalist of the competition gain automatic entry into the T20 tournament in India next season.
After 146 was set to win, the Knights set about building partnerships up front, but lost their way during the middle of the innings and the big-hitting West Indian Andre Russell did not even get a chance to come out to bat.
Returning Proteas spinner Robin Peterson picked up three wickets as he helped rip through the top order of the Knights.
Peterson first dismissed Knights opener Gerhardt Abrahams for 19, before clean bowling both Rilee Rossouw (9) and Obus Pienaar (0) to leave the home side's chase in tatters at 59 for four in the 11th over.
Peterson ended with outstanding figures of 3/21 from his four over stint with the ball.
The Cobras did not make any further breakthroughs, but were able to limit the set batsman effectively.
Rudi Second made an unbeaten 50 from 33 balls with Tumelo Bodibe also not out with 30 runs from 29 balls.
For the Knights, it meant they will have to beat the Lions with a bonus-point to gain the right to host the semi-final in their final round robin match in Kimberley on Wednesday, otherwise the Highveld side will host the playoff for a place in the final scheduled for 7 December.
The Cobras posted 145 for four in their 20 overs, courtesy of a measured, albeit uncharacteristic, knock of 64 from 61 balls by opener Richard Levi.
The normally big-hitting Levi struggled to find his timing on the slow batting surface, but together with Andrew Puttick (19) put on 54 for the first wicket.
When Puttick departed, caught Shadley van Schalkwyk bowled Werner Coetsee, Levi was joined by Omphile Ramela (34).
A 52 run partnership followed, and laid the platform for the Cobras to get to a competitive total on a tricky pitch affected by heavy rainfall in the last few days.
Van Schalkwyk was the pick of the Knights bowlers with 1/24 from his four overs.Toss: Cobras
R Levi run out (Russouw) 64
A Puttick c Van Schalkwyk b Coetsee 19
O Ramela c sub (Du Preez) b Siboto 34
K Pollard c Pienaar b Van Schalkwyk 9
D Vilas not out 4
J Ontong not out 11
Extras: (lb3, w1) 4
Total: (for four wickets) 145 - 20 overs
Fall of wickets: 1-54, 2-106, 3-129, 4-130
Bowling: Friend 2-1-9-0, Russell 4-0-31-0, Siboto 4-0-30-1, Van Schalkwyk 4-0-24-1, Coetsee 4-0-29-1 (1w), Pienaar 2-0-19-0
G Abrahams c Puttick b Peterson 19
R Hendricks b Linde 17
R Rossouw b Peterson 9
R Second not out 50
O Pienaar b Peterson 0
T Bodibe not out 30
Extras: (b1, lb6, w5) 12
Total (for four wickets) 137 - 20 overs
Fall of wickets: 1-41, 2-52, 3-54, 4-59
Bowling: Shezi 4-0-43-0 (1w), Paterson 2-0-4-0, Pollard 2-0-18-0 (1w), Adams 3-0-21-0 (3w), Peterson 4-0-21-3, Ontong 1-0-5-0, Linde 4-0-18-1
Result: Won by 8 runs.