The right-hander struck 71 (70 balls, 10 fours) out of 122 runs in a low-scoring affair at Buffalo Park where three wickets apiece from Marchant de Lange (3/18) and Ottniel Baartman (3/32) laid the foundation for the visitors.
The pair were outstanding with the ball, and aided by Ryan McLaren (2/19), shot out the hosts for a paltry 121 in 26.3 overs.
The Central Franchise, who had not won any of their previous six matches this term, then slumped to 55 for five, before Second and McLaren combined for an unbeaten 67-run sixth-wicket stand to lead their side to victory with 123 balls remaining.
It was their first win of the campaign and moved them to nine points, seven off the play-off places but still bottom of the table.
However, the Knights did all they needed to do to stay alive in the competition. After winning the toss and opting to bowl, they reduced the hosts to 34 for five in 10.1 overs with the quicks running riot.
Three of the top five were out for single-figure digits, including Eddie Moore, who ended with the second highest score alongside extras of 14.
In fact, the only reason the Warriors managed to cross 100 was because of the big-hitting exploits of Marco Marais after he plundered four sixes and a four in his 36-ball 42 that help the home side set 122.
The Knights’ chase began even more poorly after Andrew Birch (2/28) and Lutho Sipamla (1/23) left them on 13 for three in the fifth over.
Pite van Biljon carried them further forward with 18, but when he and Grant Mokoena (1) were dismissed in successive Sisanda Magala (2/26) deliveries, it opened up another opportunity for the home side.
But Second snuffed out the chance with his 16th career half-century that carried his side to the win.