IT WAS the moment Adelaide coach Brenton Sanderson said gave the Crows the momentum that ended up carrying them through to a preliminary final.

Jared Petrenko marked on the wing as the clock counted down to half time and delivered the ball to Taylor Walker, who took a contested mark and walked back to take his shot.

The siren rang, Walker lined up, and cleanly drilled the ball through the big sticks from 35 metres out on a tight angle.

Walker's first goal in what became a five-goal haul cut the half-time margin to 13 points - after it had been as high as 29 - and gave the Crows the impetus they needed to put them one win away from a Grand Final berth.

"When … you see a player or a team score a goal right on a key break, it just gave us the energy and excitement," Sanderson said.

"It put us back to 13 points down, which gave us a little bit of a spark."

It also gave Walker a push, with the 22-year-old setting the game alight in the third term.

Walker booted two quick goals midway through the term - the second of which moved the Crows within a point - and then set up Kurt Tippett in red time for the major that reclaimed the lead.

The spearhead said he had been determined to atone for his quiet game against the Sydney Swans in last weekend's qualifying final, where he kicked just 1.3 and managed only four marks.

"In big games, I like to pride myself on playing well and after last week I was pretty disappointed in my performance," Walker said.

"To come out and play well gives me a lot of confidence."

Before Walker kicked his game-changing goal after the half-time siren, he'd sprayed a couple of shots early in the game, and it looked as though history might have been repeating itself.

Walker had a second-quarter brain fade that gave away a 50-metre penalty that gifted a goal to Garrick Ibbotson after moving too close to the Fremantle player as he lined up for a tough set shot.

Ibbotson's goal pushed Fremantle's lead to 27 points, and Walker felt he had let his side down.

"I was very disappointed … I knew I had to work and get us back in the game and try and put a bit of scoreboard pressure on," he said.

Walker said he didn't allow his confidence to drop when he missed two shots at goal in the opening quarter, knowing he could turn things around if he could find his way back to his routine. 

"I had my opportunities early, just didn't capitalise on those," he said.

"I thought if I just kept working I would eventually get a bit of space on my opponent.

"I just go back and take a couple of deep breaths and think about my routine, and if I can do that, the rest will take care of itself."

Jennifer Witham is a reporter for AFL Media. Follow her on Twitter @AFL_JenWitham.