JACK Darling feels in a "better space" than ever before big games, and the star West Coast forward believes growing maturity and simpler focuses helped him swing the tense qualifying final against Collingwood.

Together again for the first time in six matches, Darling and dual Coleman medallist Josh Kennedy were gamebreakers in the win over the Pies.

MEGA-PREVIEW West Coast v Melbourne

Held to 1.4 between them to three-quarter time, the Eagles' twin towers combined for three goals and took four contested marks when the match was up for grabs.

"With the maturity I've shown, and just my focus points, I just kept at it – JK as well," Darling told AFL.com.au.

"(We told ourselves) don't drop your head or lose confidence, just keep doing what you're doing.

"As forwards, sometimes you can have a few (good) minutes or a good 10 minutes. That's what happened.

"Hopefully we can have a longer spell of purple patch rather than just the last quarter this week."

Many expect Darling and Kennedy need to be the difference for the Eagles to overcome red-hot Melbourne in Saturday's preliminary final.

Much has been made of West Coast's 11-0 record when both gun forwards are in the side, and the Eagles will pose the Demons a different challenge to last time at Optus Stadium.

Kennedy didn't play in round 22, while Darling was concussed after 10 minutes and played no further part, throwing the Eagles' structure out of whack in the 17-point defeat.

"Nathan Vardy had to play more forward, which means Scott (Lycett) was playing a lot of ruck time against Max Gawn," Darling said.

"'Gov' (Jeremy McGovern) went forward for a bit as well, so it was a bit of a domino effect.

"Hopefully, me and Joshy are back and firing this week, the team is settled and we play our role and get the job done."

One of the Eagles' most experienced September campaigners, Darling has booted an accurate 22.7 from 12 finals appearances, including three straight in last year's elimination final classic against Port Adelaide. 

He credits a spike in form late in 2017 as the catalyst for his stunning start this season, when he emerged as the AFL's dominant key forward.

The athletic 191cm tall had long threatened to join the competition's elite, and expectations went through the roof after he kicked 53 goals in just his second season in 2012.

But his four-game stretch this season of 16 majors and 41 marks – culminating in a career-best six-goal, 15-mark performance in round nine's 47-point thrashing of Richmond – was a breakout period in his career.

"I've played some good games in the years before, but I just hadn't put a block together," Darling said.

"I had a good month there for a bit, so I got a lot of confidence out of that.

"(Against Richmond) it was just one of those games where everything was sticking and it was probably the best game I've ever played."

Darling is also clearer on what he needs to do to be consistent, starting with attacking the ball in the air and refusing to be outmarked.

That, and a focus on workrate, has helped him slot 44 majors in 19 games this season – despite going goalless six times (he was injured early twice).

Now in his prime at 26, a father of one and with another child on the way, Darling is also settled away from football, which is flowing through to his form.

He is excited but still calm thinking about the opportunity in front of West Coast, and feels relaxed about performing on the big stage as the Eagles hunt a chance to right the wrongs of their 2015 Grand Final disappointment.

"Before the big games I'm in a much better space to play a better game and just be more consistent," Darling said.

"I might not be kicking your four or five goals, but I'm just making a contest and doing those little things that the club really want me to do.

"I know what to expect and, all the hype around it, you just learn how to treat it."