Fremantle outlasted Port Adelaide by seven points in a round one heavyweight bout that had all the hallmarks of a cut-throat final.
The two sides traded blows all night, but it was Freo who held their nerve late in the last quarter to win 11.9 (75) to 10.8 (68) in front of 34,099 fans at Domain Stadium.
Skipper Matthew Pavlich kicked four goals straight, including two clutch set shots in a knife-edge final term.
David Mundy produced a phenomenal last quarter with13 possessions and five clearances to finish with 29 touches for the match, while Nat Fyfe was a star throughout with 31 disposals and a goal.
Fremantle coach Ross Lyon expected a tough challenge and was proud of his side's efforts.
"It was exactly what we thought it would be," Lyon said post-match.
"You come in with maybe a little bit more anxiety but I knew our group would give great effort and that's what they did tonight. Their last quarter was fantastic for will power and desire."
Port was brave and unlucky not to come out on top. Ollie Wines was sensational with 27 touches and two goals, while Brad Ebert and Robbie Gray ran their opponents ragged to gather 34 and 31 touches respectively.
The Power used their run and superior field kicking to great advantage all night but Freo won critical contests at the coalface in the last quarter and kicked straight when it mattered most.
Port suffered a huge blow pre-game when ruckman Matthew Lobbe was a late withdrawal with quad tightness.
John Butcher was the late inclusion for his first game since round three last season, leaving Patrick Ryder to shoulder the ruck load after not playing the entire pre-season.
Fremantle dominated the hit-outs as a result, 51-25, and the clearance differential (41-30), although Port negated the advantage relatively well for three quarters with outstanding run and transition from defence.
The first term was an arm wrestle but the difference between the two sides was Port's field kicking. The Power kicked at 77 per cent in the opening term compared to Fremantle's 60 per cent, but Port missed its chances in front of goal.
Freo lifted in the second term with Pavlich drilling a set shot from 55m to put his side in front for the first time.
They led by as many as 10 points after Danyle Pearce threaded through a snap from a tight angle, but the lead could have been far greater.
Freo failed to clear a ball on their own goalline and Jake Neade pounced for an easy goal. Then Hayden Ballantyne fumbled a metre out at the other end to butcher a goal and Port traversed the length of the field for Brad Ebert to score the easiest of goals.
The pressure in the third term lifted another notch with neither side able to find breathing space.
Danyle Pearce nailed a high pressure set shot from 50m after Justin Westhoff missed from directly in front minutes earlier.
But Fremantle's inaccurate field kicking hurt it again with Port burning the Dockers on the counter-attack. A turnover at half-back led to a simple goal for Wingard, while another at half-forward finished with Wines nailing a set-shot for nine-point lead.
Fyfe and Pavlich combined to steady the nerves for Fremantle and the margin was just three points at the last change.
Wines won a holding the ball decision 30m out to kick the first goal of the last quarter and put Port in the box seat.
But Mundy and Pavlich stood tall to restore Fremantle's lead and they sealed the result when Zac Clarke ran down Jasper Pittard in defence to give Ballantyne his second.
Travis Boak kicked arguably the goal of the night to make the last two minutes interesting but the Power fell seven points short.
FREMANTLE 2.1 5.3 7.5 11.9 (75)
PORT ADELAIDE 2.5 5.5 7.8 10.8 (68)
GOALS
Fremantle: Pavlich 4, D. Pearce 2, Ballantyne 2, Fyfe, Walters, Neale?
Port Adelaide: Wines 2, Ebert, Wingard, White, Neade, Schulz, Butcher, Wingard, Boak
BEST
Fremantle: D. Pearce, Fyfe, Pavlich, Mundy, Barlow, Duffield
Port Adelaide: Ebert, Wines, Polec, Gray, Boak, Wingard
INJURIES
Fremantle: Chris Mayne (ankle)
Port Adelaide: Lobbe (quad) replaced in selected side by John Butcher
SUBSTITUTES
Fremantle: Matt de Boer replaced Chris Mayne during the final quarter
Port Adelaide: Angus Monfries replaced Alipate Carlile during the final quarter
Reports: Brad Ebert for tripping Cameron Sutcliffe in the final quarter
Umpires: Foot, Margetts, Meredith
Official crowd: 34,099 at the Domain Stadium
