Emerging forward Brennan Cox has repaid coach Ross Lyon's faith by leading Fremantle to a nail-biting three-point victory over Adelaide at Optus Stadium on Sunday. 

With Cam McCarthy omitted from the team, the Dockers needed Cox to stand up and the second-year tall delivered a career-best four-goal haul to keep Freo's slim finals hopes alive and dent the Crows' top-eight chances. 

The rebuilding Dockers' fifth win for the season at home ended a three-game losing streak and was a massive upset by a youthful outfit featuring 13 players with under 45 games' experience.

However, the victory could be soured with star Michael Walters reported for headbutting Tom Doedee and could also face scrutiny for striking Adelaide defender Jake Kelly during the 10.11 (71) to 9.14 (68) result.

Adelaide's sixth loss – and third in a row – places last year's grand finalists under mounting pressure to make something from 2018.

The Crows' injury crisis could have deepened, too, with Luke Brown being carried from the field in the final term with a right ankle problem.

Both sides came into the clash undermanned, with the Crows missing seven first-choice players and the Dockers without superstar Nat Fyfe (suspension) and Aaron Sandilands (concussion), among others.

Lyon called on his troops to stand up without arguably their two most important players and he would have been thrilled by the response.

The Dockers burst out of the blocks, booting five goals to one in their best first term for the season and held on late after Adelaide threatened a comeback in a see-sawing contest.

Cox finished with 19 disposals and seven marks in a brilliant performance in wintry conditions, but there was plenty of promising efforts from a young outfit.

No.5 draft pick Adam Cerra (30 disposals, eight inside 50s) had the best game of his short career, while Connor Blakely (30) was back to his best and Ed Langdon (25, one goal) continued his excellent campaign. 

Eddie Betts, who declared the match Adelaide's most important game this year, rued a bad day in front of goal, with the small forward returning 2.6 and missing three crucial shots in the final term.

Down by 11 points at the final break, the Crows charged but couldn't put the score on the board, kicking 2.5 to 1.3.

Gun recruit Bryce Gibbs (28 disposals) did his best to lift Adelaide, while Matt Crouch (25) and Paul Seedsman (24) tried hard, but it wasn't enough.

Almost everything went Freo's way in the first term once Bailey Banfield ran into an open goal 90 seconds into the contest.

Recalled veteran Hayden Ballantyne was buzzing at ground level, Cox brought his kicking boots and Tommy Sheridan (two goals) threaded the eye of the needle, with Freo's fast-paced footy bringing the crowd to life. 

The Crows were all at sea in attack, even with skipper Taylor Walker back, but the Dockers were switched on and swarmed all over the visitors to take a 22-point lead into the opening change.

But, with so much at stake, Adelaide flicked the switch in the second term and got on top around the contest – winning contested ball 37-28 and clearances 11-6 for the quarter.

Mobile forward Josh Jenkins slotted two goals, cleverly set up Sam Gibson for another and Betts got dangerous as the Crows piled on six unanswered majors. 

However, the contest swung again in the third, with Walters (17 disposals) inspirational, as Freo ramped up the tackling pressure and drilled four straight goals to reclaim an 11-point edge at the last change.

The Crows were desperate, highlighted by a superb Tom Doedee chasedown on Walters, but couldn't find an avenue to score.

Heading to the last term, only one major had been scored at the eastern end – which Freo was kicking to – and Cox's solitary goal for the Dockers in the fourth quarter was enough for them to hold on for an epic against-the-odds victory.

FREMANTLE            5.2   5.6   9.8   10.11 (71)                  
ADELAIDE               1.4   7.6   7.8   9.14   (68)           

GOALS
Fremantle:
Cox 4, Sheridan 2, Banfield, Ballantyne, Tucker, Langdon
Adelaide:
Jenkins 2, Betts 2, Douglas, Gibson, Walker, Greenwood, Poholke

BEST 
Fremantle: Langdon, Cox, Cerra, Pearce, Hamling, Wilson
Adelaide: Gibbs, Gibson, Doedee, Betts, Douglas

INJURIES 
Fremantle: Nil
Adelaide: Luke Brown (left ankle)

Reports: Michael Walters for headbutting Tom Doedee

Umpires: Margetts, Hosking, Whetton

Official crowd: 33,421