The Dees kicked eight of the first nine goals to take a stranglehold on the contest before halftime and cruised to a 15.9 (99) to 9.13 (67) victory at Marvel Stadium on Sunday.
It improved Melbourne's record to 6-3, with only percentage separating them from fourth-placed Brisbane, ahead of a high-stakes clash with Hawthorn next round.
King believes Pickett will be free to play despite the explosive match-winner again facing scrutiny from the match review officer.
Pickett had his hands out reaching for the ball and did not elect to bump his opponent when he made high contact with Waterman in the opening 20 seconds.
The 24-year-old, who has been suspended multiple times for bumping opponents in the head, was clearly concerned about the incident in the aftermath.
But King felt his star man made a "legitimate play on the ball" on this occasion.
Waterman was sore but got up to take his free kick and was one of West Coast's best players, finishing with three goals and a game-high 13 score involvements.
"Kozzy's a leader, he's matured a lot as a player and he knows how important he is to us," King said.
"The way he plays the game is on the edge at times because of the talent he's got and how hard he is around the footy.
"When we saw the replay, we got the message pretty quickly to Koz that he was making a play on the ball and you'll be fine."
Pickett did not have his usual level of impact under close attention from Brady Hough and Willem Duursma, finishing with 14 disposals and one goal.
King "looked after" Pickett by playing him as a deep forward at times, with an eye on the Demons' six-day break leading into the Hawthorn clash.
"He did what he needed to do to help us get the result," King said.
"He's set a pretty high benchmark for himself and we don't need Kozzy to do anything super for us all the time.
"It's nice to find a way to win without him being his dominant self."
Ruck star Max Gawn also spent plenty of time stationed in attack as Tom Sparrow (24 disposals), Jack Steele (26), Caleb Windsor (22) and Kade Chandler (18) spread the load.
Jacob van Rooyen (five goals) was the focal point in the Dees' attack, where third-gamer Paddy Cross (three) also featured among nine goal-kickers.
After winning two of their first three games, West Coast (2-7) have now lost six in a row by an average margin of 62 points.
The Eagles also lost defender Harry Edwards to his third concussion of the year after an accidental elbow from teammate Elliot Yeo in the opening term.
"I'm really concerned for Harry," West Coast coach Andrew McQualter said.
"It's really sad and unfortunate that he wasn't able to play for us today but it's bigger than that for Harry right now.
"He's in great spirits, for what it's worth. He is walking around and he was at halftime, so he's in a good spot, but he did fail his SCAT test."
McQualter was unsure whether Edwards would be sent to the AFL concussion panel, which forced former West Coast defender Jeremy McGovern to retire last year.
The Eagles coach felt turnovers and simple errors cost his side dearly against Melbourne, especially early in the game, but was pleased his side showed fight after the margin reached 46 points in the third quarter.
Tom McCarthy (30 disposals) and Milan Murdock (25) won plenty of the ball for the visitors and Harley Reid fought hard with 21 touches, five clearances and one goal.
8°C