PORT ADELAIDE have secured a place in the 2019 SANFL Grand Final following a four-point win over Glenelg in a thrilling second semi final at the Adelaide Oval on Sunday.

In an incredible finish, the Magpies held a 16-point three quarter time lead before the Tigers came home in a flurry to take the lead at the 11-minute mark of the final quarter.

Late goals to Todd Marshall and Tobin Cox put Port back in front and the men from Alberton managed to hang on in a frantic final five minutes to claim an 11.10 (76) to 11.6 (72) victory.

Trent McKenzie was outstanding in his role across half back all afternoon and finished with 28 disposals, while his partner in crime Jarrod Lienert had 25 touches for the game.

Early in the contest, the Magpies gained the initial momentum with young key forwards Marshall and Billy Frampton kicking the first two goals in the opening six minutes.

Finding themselves 12 points down in the blink of an eye, the Tigers locked it down, maintained possession and eventually Matthew Snook registered their first major thanks to a free kick 30m out from goal directly in front.

Ten minutes later Glenelg found the League’s most productive forward Liam McBean on the lead who slotted his side’s second goal to edge the Bays in front.

The rest of the term became an arm wrestle as both sides struggled to capitalise on goal scoring opportunities.

Glenelg’s Marlon Motlop sent another shot wide for the Tigers and the Magpies made them pay with an end to end run from the kick-in which resulted in a classy goal around the corner from Kane Farrell.

The siren rang just seconds later and Port held a five-point lead at quarter time.

Lienert was finding plenty fo the ball across half back and collected 12 disposals in the first term.

Glenelg came storming out of the blocks in the second quarter as McBean struck his second goal from the paint of 50, before Bradley Agnew streamed away from the centre bounce restart to set up a second major within a minute.

After quiet starts, Willem Drew and Jack Trengove worked their way into the game and as a result the Magpies started to find the footy and force it forward.

Aidyn Johnson lit up the second term with a 10-minute purple patch. First he danced around two defenders to spot up Sam Mayes 25m out. Three minutes later he capitalised on a McKenzie long bomb inside 50 by strolling into an open goal.

Then the livewire forward capped it off with a fantastic snap from the scoreboard pocket to put the Magpies up by seven points at half time.

After nine disposals in the first quarter from Tiger Luke Partington, Port captain Cam Sutcliffe went to the dangerous midfielder and reduced him to just one touch in the second term.

The rain started coming down after half time as the pressure lifted again in a match that had six lead changes in the first two quarters.

Glenelg locked the ball in its forward half for the opening six minutes of the third term, but it was the Magpies who drew first blood when they again went end to end for a Drew goal.

Two third term goals from Motlop kept the Tigers in the game as Port controlled proceedings.

While continuing to nullify Partington's influence, Sutcliffe went on the attack himself as the skipper goaled with a fantastic snap goal in front of the Port cheersquad to put the Magpies ahead by 15 points.

Sixteen points separated the two sides at the final break and the Bays threw everything they could at the fading Magpies, who had just two on the bench after Sam Mayes left the ground with a head knock.

Glenelg kicked three goals in the first 11 minutes through Brad Close, Josh Scott and Partington, who began to find the footy again as Sutcliffe was pushed up onto a wing as cover for the injured Mayes, to put the Tigers in front.

Port steadied in a manic final term to reclaim the lead and hang on to a memorable win that sent it to the decider.

It was the first time the Magpies had beaten the minor-premier Tigers all season and there were plenty of contributors.

McKenzie and Lienert were fantastic, while Johnson booted three important goals, Drew and Joe Atley both had 22 disposals and Ladhams had 20 disposals and 26 hitouts.

Glenelg will face Adelaide in next Sunday’s preliminary final after the Crows defeated Norwood in the day's earlier Semi Final, while the Magpies will enjoy a week off before facing the winner on Sunday, September 22.

SCORES:

Port Adelaide: 3.2, 6.4, 9.8, 11.10 (76)

Glenelg: 2.3, 5.3, 7.4, 11.6 (72)

DISPOSALS: McKenzie 28, Lienert 25, Atley 22, Drew 22

GOALS: Johnson 3, Marshall 2, Cox, Drew, Farrell, Frampton, Mayes, Sutcliffe

BEST: McKenzie, Lienert, Drew, Marshall, Sutcliffe, Garner

CROWD: 11,406