WEST Coast players have to "earn their keep" or they will find it tough to hold their spot, Eagles coach Adam Simpson says.

In Saturday night’s 54-point win over Melbourne in Darwin, experienced midfielder Scott Selwood started as a substitute while Matt Rosa played for East Perth in the WAFL.

Five talking points: Melbourne v West Coast

Simpson made no apologies and said such selection dilemmas were the sort of challenges clubs want to face as they rise up the ladder.

"You have got to earn your keep and he [Selwood] was a bit off last game and started as sub this week," Simpson said.

"Our midfielders have been rotating through that position a little bit … it was his turn this week."

The Eagles' midfield depth was questioned throughout 2014, however the club has kept playing first-year midfielder Liam Duggan and is benefiting from the development of Dom Sheed throughout last season.

WATCH: Adam Simpson's full post-match media conference

Other midfielders such as Andrew Gaff, Luke Shuey and Chris Masten have become consistent performers in 2015.

"It's tough for spots but that is the challenge we want to be in. We need to find a balance between development and playing players who are in form as well so we'll continue to do that," Simpson said.

He said he was uncomfortable throughout the game because Melbourne forced the Eagles to play to the Demons' style for the first three quarters, but was happy they were able to break the game open eventually.

Gamebreaker: Five-star Darling

In the end the Eagles had 34 scoring shots compared to 15 but until the last quarter the game felt like a relatively tight contest.

Key forwards Jack Darling and Josh Kennedy were the difference with seven goals.

Darling, who kicked five, has now kicked nine goals in the three games since he returned.

Simpson said the 23-year-old is a crucial player.

"Without a doubt. People have got to plan to play against him," Simpson said.

"Today was his day and next week it might be someone else's."