FREMANTLE coach Justin Longmuir saw the warning signs eight days earlier when his team was in the process of beating North Melbourne by 51 points. 

Amid the big midfield numbers, four-goal efforts and another sparkling performance from David Mundy, he had witnessed a worrying defensive effort all over the ground that had left his backline exposed. 

Longmuir was quick to point out the final margin had much more to do with the Kangaroos' inaccuracy than anything his team had done and he had been "disappointed" in the way the Dockers defended. 

Fast forward to another Western Derby loss and the way the Dockers are defending is now under the microscope, both around the ground and when they have the ball on the last line. 

The stat that best captures their poor defensive effort against the Eagles is the turnovers the Dockers were unable to force, with West Coast handing the ball back just 51 times compared to the Dockers' 62. 

The Dockers had forced at least 70 turnovers from their opponents in every game they had played up to round seven, and they had fewer turnovers than their opponents in each of their four wins. 

This stat against the Eagles showed the team's pressure without the ball was well down and needs urgent correcting against Brisbane this week.

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Drill down further and you see that 23 of the Dockers' own turnovers were made by defenders.  

"We didn't handle their pressure in our back 50," Longmuir said after the game. 

"We either kicked it back to them or gave it to someone under more pressure."

The most obvious example of this came in the second quarter and left Longmuir with his head in his hands in the coaches' box. 

The ball was pumped inside the Dockers' defensive 50 and ended up with Tobe Watson, who handballed to Brennan Cox under pressure, who then did likewise to Heath Chapman. 

The young Docker, who showed grit to play through a shoulder issue, turned it over to Jack Darling in front of goal and Fremantle's lead was cut to five points. 

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The Eagles' next goal came from a kick-in, with Alex Witherden sending the ball long down the middle and Nathan Vardy taking a relatively easy mark on Rory Lobb in the centre square. 

He then sent the ball long and wide to an open Jarrod Brander, who played on and kicked long to Jake Waterman, who got out the back and took a contested grab opposed to Watson. Three kicks and three marks from goal line to goal line. 

The pressure factor metric used by clubs came in at 162 for the match, well below the League average of 180, and when your pressure is off against the Eagles they cut you apart, like they did to set up Waterman's goal. 

West Coast loves to mark the ball when allowed, and it took 74 second-half marks to the Dockers' 43, finishing the match with 119 to 84. 

It was a "reality check", Longmuir said, for a team that had won plenty of fans in the past month and will be prone to ups and downs while it works through a development phase. 

"The key in review will be to own what we can control," Longmuir told 3AW on Monday night. 

"There's plenty that we are responsible for yesterday, so we need to own that and need to improve on it. 

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"We've played some good footy this year, but realistically we haven't played the big boys … we need to bounce back this week and redeem ourselves." 

Defensive pressure is a part of the game coaches talk about being a non-negotiable for a developing side and team defence had quickly become a strength of the Dockers. 

Longmuir will be keen to see both return as they prepare for the prospect of a fortnight on the road against Brisbane and Essendon.