England needed to bat for most, if not all, of the final day to keep the series alive but Josh Hazlewood hastened their demise with 5-48 as the tourists lurched from an overnight 132-4 to 218 all out.
Australia therefore take an unassailable 3-0 lead in the five-match series and England captain Root has demanded a response from his side when they head to Melbourne on Boxing Day.
“It’s very difficult to take,” said Root. “Fair play to Australia, they’ve outplayed us in all three games and we’ve got to be better.
“We’ve got to make sure we go to Melbourne and prepare well and put in really good performances there.”
Root was unwilling to draw too much attention to the controversy earlier in the day, when overnight rain had somehow seeped under the covers and onto the pitch.
England coach Trevor Bayliss voiced his concerns to broadcasters, during morning deliberations, that conditions had been rendered too “difficult ... maybe even a little dangerous”.
But Root said: “When we got here this morning it definitely wasn’t fit to play, it obviously dried up as the sun and wind got to it and they obviously worked very hard to get it right. I think by the end there it was probably fit to play.”
Australia captain Steve Smith led by example with a career-best 239 to help his side to 662-9 declared in response to England’s 403 all out.
Despite some resistance from Dawid Malan, who followed up his first-innings century with a defiant 54 on Monday, Australia never looked back after Hazlewood took the wicket of Jonny Bairstow with his first ball of the day.
And Smith paid a special tribute to frontline bowlers Hazlewood, Mitchell Starc, Pat Cummins and Nathan Lyon after they clinched a series victory at the earliest opportunity.
He said: “I’m just so proud of the boys. The way we’ve been able to win this series and wrap things up here in Perth and get that urn back, it’s been quite amazing.
“The (bowlers) have done a terrific job to get us the 20 wickets that we’ve needed in every game. We haven’t won a toss and we’ve probably had the toughest of the conditions as well. I’m just really proud of everyone in that dressing room.”