After toppling rampaging ladder-leaders Fremantle and last year's grand finalist Geelong in the previous fortnight, GWS suffered an unfathomable three-point upset loss to Essendon on Sunday.
The Bombers had won just one of their past 30 games and came in off a 90-point belting from Brisbane, who the Giants destroyed with a record 14-goal third quarter in May.
Finalists the past three seasons, GWS are in danger of not even qualifying for the wildcard round due to their habit of dropping games they should win.
As well as the Bombers, GWS have lost this season to West Coast, Carlton and St Kilda (twice).
"It must be some sort of mental block there that we haven't put our finger on yet and been able to solve," Kingsley said.
"That's all of us, we haven't managed to fix that.
"Until we do, we're not going to become the team that we want to become, and we've got plenty of work to do in that space.
"We've got sports psychologists at the club provided to us to be able to tap into.Â
"We've got the resources there, we've just got to do a better job, plain and simple."
In an added blow for the Giants, captain Toby Greene suffered a quad injury that will be scanned on Monday.
Finishing the match with ice on his quad, Greene will miss at least next Saturday's Sydney derby.
"He lunged for a tackle and just felt his quad," Kingsley said of Greene.
"I don't know any timelines on that at all, but we're on a six-day break into the Swans so - a big match - and he won't be available for that."
GWS sit 11th, but would have jumped ahead of the Saints into 10th - the wildcard zone - had they taken care of Essendon.
But going by the Giants' fluctuating form they are every chance to topple the second-placed Swans.
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