Having sent the Dolphins in to bat, the Cobras dismissed them for just 174 and had closed to within 44 runs with six wickets in hand as they reached stumps on 130 for four.
The Cobras had been embarrassed last week at Newlands as they slumped to an eight-wicket defeat at the hands of the Highveld Lions, but a full house of four bowling bonus points has seen them build on their 11.68-point lead at the top of the table.
Left-arm paceman Beuran Hendricks led a top-class bowling effort by the Cobras as he took five for 47, a career-best effort in the four-day competition.
A defiant 92 by opener Divan van Wyk was all that stood between the Dolphins and a total disaster at a cloudy Newlands.
Fast bowler Kyle Abbott, rapidly becoming a candidate for higher honours, kept the Dolphins in the contest as he claimed the important wickets of Alastair Gray (36) and Justin Ontong (28), finishing the day tied with Cobras seamer Johann Louw as the competition’s leading wicket-taker with 30 scalps.
Left-arm spinner Keshav Maharaj had a well-set Stiaan van Zyl (29) caught at short-midwicket the ball before Ontong’s dismissal for a double strike by the Dolphins, but Qaasim Adams (14*) and Dane Vilas (4*) batted out the rest of the day for the Cobras.
The second-placed Warriors had allowed the Knights off the hook in their match in Bloemfontein, after reducing the hosts to 135 for seven.
The most impressive of centuries by Rilee Rossouw, who reached three figures off just 107 deliveries despite the chaos around him, and the clean-hitting of the in-form tailender Dillon du Preez, who followed up his century last weekend against the Titans with an unbeaten 88 including 13 fours and two sixes, lifted the Knights to 268 all out.
Paceman Gurshwin Rabie was the pick of the Warriors attack, ripping through the middle-order and finishing with four for 63 in 19 overs.
Off-spinner Simon Harmer removed the lower-order to take three for 67.
Du Preez was then given the new ball as reward for his heroic efforts down the order and he trapped Michael Price (0) in front of the stumps with his second delivery.
Captain Davey Jacobs was caught behind off left-arm seamer Romano Terblanche for 18 as the Warriors slipped to 36 for two, but the experienced duo of Arno Jacobs (33*) and Ashwell Prince (24*) had lifted the Eastern Cape side into a better position on 79 for two by stumps.
In Johannesburg, the Titans seemed to have looked upwards at the overcast sky rather than downwards at the pitch when they won the toss and sent the Lions in to bat, the home side cruising to 124 for one at lunch as Dominic Hendricks (74) and Temba Bavuma (62) added 112 for the second wicket.
But the Titans bowlers tightened up considerably when they came out for the afternoon session and claimed five wickets for 82 runs.
When Cliffe Deacon joined fellow veteran Zander de Bruyn at the crease, the Lions had slumped to 223 for six, but the left-hander scored a valuable 20 to help switch the momentum.
When De Bruyn was eventually trapped leg-before by spinner Shaun von Berg for a fighting 65, the Lions had climbed to 303 all out, Imran Tahir (14*) sharing in a rollicking last-wicket stand of 41 in 6.2 overs.
David Wiese was the most successful of the Titans bowlers with three for 47 in 15 overs, while the probing seam bowling of Ethy Mbhalati and Rowan Richards earned them two wickets apiece, although the left-arm quick left the field with injury during the important seventh-wicket stand between De Bruyn and Deacon.
The Titans openers then survived the hostile new-ball spell of Chris Morris as they reached 23 without loss. Jacques Rudolph, the returning international, was dropped by Bavuma in the gully on four in the penultimate over of the day, bowled by the rather more wayward Hardus Viljoen.