England bounced back from defeat to South Africa in their series opener by winning match two in Johannesburg to make Sunday's final fixture, live on Your Site YouTube, a decider.
A much-changed side triumphed 61-49 with the Vitality Roses - ranked No 4 in the world, one place higher than their opponents - having gone down 52-48 on Thursday.
Tweaks, which included Lois Pearson moving to wing attack, paid off in the must-win encounter on Saturday.
Helen Housby's penalty left the scores level at 13-13 after the first quarter but South Africa took control after that and opened up a seven-goal lead before Funmi Fadoju led a rally from the away side.
The Vitality Roses took the 'championship quarter' 9-18 to carve out an eight-goal cushion at 44-36 with 15 minutes remaining and they did not falter from there.
Watch the crunch third match live on Your Site YouTube from 2pm on Sunday.
Head coach Jess Thirlby said: "I think we were smarter with the ball, moved it a little bit better around some excellent defence.
"I think you saw the passion and commitment defensively from the whole unit including our attacking players to contribute, to wear down and force a little bit more error so that we could capitalise off it. It was another fantastic game and sets up [Sunday] brilliantly."
England captain Fran Williams, who produced two key interceptions in the third quarter and was named player of the match, added: "I think we showed such composure in the way were able to weather that storm early. South Africa came out all guns blazing, as we knew they would.
"They've been playing some amazing netball this series, so I think we did so well to go goal-for-goal and then take our moments in that second half to really put on that scoreboard pressure.
"I loved the way we played the last quarter. We didn't do anything too flashy, we were happy to sit in and go goal-for-goal knowing we'd done the work. Smarts got us over the line."
Looking ahead to the deciding game, Williams added: "I think we're going to need to step it up a gear.
"How exciting for us, on both sides, to practice playing in those must-win games. That's what we want in a Commonwealth Games year."
