Sciver-Brunt collected her third player of the match award in four outings after hitting 81 not out as England powered their way to a record 213 for five.
England's bowlers then took their turn to put the pressure on, restricting Pakistan to 99 for nine.
Sciver-Brunt went to the wicket after England lost two wickets in the first five overs through attacking shots.
But she and Danni Wyatt, who made 59, continued to be aggressive as they added 74 for the third wicket off 42 balls. The scoring reached a crescendo when Sciver-Brunt and Amy Jones (47) put on 100 for the fifth wicket off 45 deliveries.
"We agreed in our planning to put the pressure back on the other team," said Sciver-Brunt.
"That means we take it to the bowlers, not so much to knock it around and put a partnership together but try to put the bowlers under pressure and play to your strengths."
She said the policy was similarly aggressive with the ball.
"We really focus on taking wickets," she said.
It was England's first appearance of the tournament at Newlands, where the semi-finals and finals will be played, and Sciver-Brunt said England had targeted their final group match as "a chance to show everyone what we’re about, to show off a bit".
England finished first in Group Two with four wins from four matches and will meet the second-placed team from Group One in the semi-finals on Friday.
The previous highest total in a Women’s T20 World Cup was 195 for three by South Africa against Thailand in Canberra in 2020.
Katherine Sciver-Brunt had Sadaf Shamas caught behind off the second ball of Pakistan's reply and Pakistan collapsed to 54 for seven before Tuba Hassan, batting at number nine, made a spirited 28 off 20 balls.
Pakistan were captained by Nida Dar in the absence of Bismah Maroof, who had a groin injury.
"We have to learn from these kind of matches," said Dar. "We’ve played two good matches here (in South Africa) so we'll take positives from that. It's time for new blood to come up."
Brief scores: England 213-5 in 20 overs (D. Wyatt 59, N. Sciver-Brunt 81 not out, A. Jones 47; Fatima Sana 2-44)
Pakistan 99-9 (K. Sciver-Brunt 2-14, C. Dean 2-28)
Result: England won by 114 runs
Toss: England
