Port Adelaide has knocked its arch rival Adelaide out of the top eight with a gritty 12-point victory at AAMI Stadium on Sunday.

In a game of swinging momentum, the Power finally stood up in a pressure-filled final quarter to win 13.14 (92) to 11.14 (80).

The team from Alberton was challenged twice during the final half an hour but weathered the storm on both occasions to break a five-game losing streak.

The result gives Port a 13-12 advantage in Showdowns and leaves Adelaide to reflect on its fifth loss in a row.

The Power's struggling forward line lifted collectively and was the difference between the two teams.

Daniel Motlop and Brett Ebert were at their opportunistic best and collected four majors each while Justin Westhoff kicked the goal of the day.

Warren Tredrea had one of his better Showdowns in recent times finishing with 18 disposals.

Danyle Pearce, who's been criticized for going missing in the clinches, was awarded the Showdown Medal for his desperate approach and 24 disposals.

Two late goals topped off a busy game by Michael Doughty while Chris Knights and Brad Symes collected plenty of possessions.

But in the end the Crows made too many fundamental errors to win.

Port dominated the first quarter but didn't hurt Adelaide on the scoreboard.

They entered their forward 50 15 times, had more tackles and were getting good use of the ball thanks to Dean Brogan and Brendon Lade.

Their forwards were also showing some promising signs with Motlop spearheading the attack with two majors.

But the Crows made the most of their opportunities with Scott Stevens' long goal ensuring the difference was only 11 points at the first change.

After the teams exchanged goals in the early stages of the second term it was Adelaide's turn to control proceedings.

It had a high possession count, was winning the contested footy and trapped the ball in attack with some excellent pressure from its forwards.

The Crows registered seven behinds in a row before Bernie Vince put them in front with a strong mark and straight kick from just in front of the goal square.

Their hard work was rewarded with a two-point lead at the long break.

The third quarter lived up to Showdown folklore with neither team giving an inch in a tough and sometimes scrappy arm-wrestle.

But it was the Power that headed into the final quarter on a high after kicking the last two goals of the stanza.

Nathan Lonie, who was denied a major