MEMO: Melbourne fans.

If you think the Demons will win the preliminary final against West Coast in Perth largely because they did it in round 22, here's some sobering reading.

That Sunday afternoon at Optus Stadium five weeks ago, when Melbourne sealed a finals berth for the first time in  12 years with an emotion-charged 17-point win, the Eagles were without their gun forward duo Josh Kennedy and Jack Darling.

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Technically, Darling played that day but he was knocked out early, leaving the home side a player short, and an important player at that.

Meanwhile, Kennedy was sidelined with a shin injury.

Melbourne veteran Jordan Lewis, possibly indulging in some mind games, has suggested the Eagles are more predictable when Kennedy and Darling play – but they are also far more formidable.

In fact, West Coast is yet to be beaten this year when 'JK' and 'JD' have worked in tandem.

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Arguably the AFL's most dangerous key forward combination, they have played together 11 times this season, tallying 61 goals (Kennedy 34 and Darling 27) to help their team to a perfect record and an average winning margin of 31 points.

This all-conquering stretch includes wins over Richmond, Greater Western Sydney (away) and Collingwood (twice).

West Coast has won 11 of the 12 games Kennedy has played this season, the only blemish being against Sydney at the SCG in round 13 when, not coincidentally, Darling was sidelined.

Ominously, the dynamic duo has also won their past seven games together at Optus Stadium, contributing 45 goals (Kennedy 25, Darling 20) to an average winning margin of 36 points.

Overall, they have joined forces to win their past 11 games at home (including their last four at Domain Stadium last year).

Since mid-2015, they have a 34-4 record at home when occupying the same forward line.

From 2015-18, West Coast is 4-3 in finals with its two sharpshooters.

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Their most recent loss in Perth together was by just eight points to the Giants back in round 10 last year when, pivotally, Kennedy hobbled off early in the last quarter with a calf injury.

When they have been forced to cope without both stars this year the Eagles are 1-2; without Kennedy only they are 4-3; and without Darling only they are 0-1.

Dual Coleman medallist Kennedy, 31, returned in the Eagles’ home qualifying final against Collingwood, when he and Darling, 26, ultimately proved crucial in a thrilling victory.

Kennedy was scoreless in the first half against Magpie miracle man Tyson Goldsack but imposed himself in the second half when he contributed 2.4 and threatened to win the game off his own boot, while Darling kicked two goals in a frantic final term.

Darling has 44 goals from 19 games this season while Kennedy has 36 from 12.

Kennedy and Darling in same team this year