The nail-biting victory - in the 400th recorded game between the traditional rivals since their first encounter in 1878 - put the Magpies a game clear of the second-placed Sturt and increased its percentage with one round to play.
Even if the Magpies lose to Glenelg next week, the Double Blues will need to defeat South Adelaide by more than 20 goals to take top spot.
VOTE FOR YOUR BEST IN THE ENERGYAUSTRALIA MAGPIES FANS' MVP
While the minor premiership isn't officially secure, a guaranteed double-chance is, and Port Adelaide will use next week's game against Glenelg as the perfect dress rehearsal for its first SANFL finals campaign since 2008.
Sunday's triumph did not come without a fight, as Port Adelaide struggled to find its grove in the first term while the Redlegs suffocated the early play and controlled the opening quarter - had they been accurate, the Magpies could have faced a far greater deficit than six points at quarter time.
Norwood recorded five more inside 50s and more than doubled the number of scoring shots at the first break, but Port's defence worked hard to heighten the defensive pressure and keep a stake in the game.
Acts of desperation from Sam Gray, skipper Steve Summerton and Paul Stewart helped the home side reap reward for their efforts pushing forward when Robbie Young and Nathan Krakouer booted four goals between them to help Port Adelaide to a 17-point buffer at the main break.
But Norwood were relentless and started the second half with a bang as the more desperate side that beat the Magpies to almost every contest.
The Redlegs booted four goals to the Magpies's two in a tight quarter to leave just two points separating the rivals at the final break.
But the Magpies held strong and with key forward Mason Shaw was the only goal scorer for the final term, the Magpies remained composed to hold off the defending premiers.
Port Adelaide's final home-and-away game is against Glenelg at Glenelg Oval on Saturday 23 August at 2:10pm.
SCOREBOARD
PORT ADELAIDE 2.1 6.3 8.4 9.6 (60)
NORWOOD 2.7 2.10 6.14 6.15 (51)
PORTADELAIDEFC.COM.AU'S BEST
Gray, Summerton, Clurey, Krakouer, Newton
GOALS
Young, Krakouer 2, Hitchcock, Amon, Stewart, Gray, Shaw
INJURIES
TBC
REPORTS
Nil
