Phys Ed, missing former Silver Ferns shooter Jo Morrison, faced a mammoth task against the defending champions and made a nervous start to the game.
A goal for goal start was followed by a Phys Ed turnover that gave Southern the chance to push ahead.
Steel players Gina Crampton and Te Paea Selby Rickit led the Southern attack, making easy work of the Phys Ed defensive end.
However, Phys Ed fought hard to stay in the game, and the Magpies led only 13-12 at the first break.
Southern made changes at the start of the second quarter, bringing Zoey Flockton into wing attack and Bethany Robertson into wing defence, and it paid dividends.
The defensive pressure of Southern captain Tessa Bekkers and Hapai Selby Law was smothering and Phys Ed had to work hard for every pass and goal.
Phys Ed captain Sophie Johns and Erin Hughes struggled to find their combination and started running into each other's space, throwing off the attack end's timing as the students trailed 29-21 at halftime.
Phys Ed's defensive end of Laura Overton and Abby Erwood had been a strength of the side at the back end of the season, but Southern did its homework and successfully reduced its influence on the match.
Midway through the third quarter, the match was in the bag for Southern, and despite changes from Phys Ed in the shooting circle, the lead was too big to overcome.
Southern coach Georgie Salter said her side brought its ''A game'' to the final.
''Our defensive end has really held us together while our young attack end was coming together during the year and they again had another great game,' Salter said.
''We really did our damage in the third quarter, and then started to play some expansive netball in the fourth quarter for everyone watching to enjoy.''
Phys Ed coach Alice Wells said it was a tough way to end the season.
''Not the way that we wanted to end the season. Without Jo [Morrison], it was always going to be tough, and our combinations didn't flow as a result,'' Wells said.
''We are really, really proud to even make the final, and even though it doesn't really reflect the season, we have to keep our heads up high.
''The girls kept fighting. They stuck at it and played until the final whistle.''
College A beat a late finishing University Albion A 62-52 to claim third place.
By Jaimie Keay.
