Australia retained the Ashes on Sunday as a 185-run loss at Old Trafford dashed England's hopes of regaining the urn.

For the first time since 2002-03, Australia ensured the Ashes will remain in their grasp - Marnus Labuschagne and Josh Hazlewood dealing the final blows in a drawn-out defeat for the hosts.

While one Test remains for England to level the series, talk has already turned to where it all went wrong for Joe Root's side - Steve Smith's supreme batting aside.

The World Cup triumph, and even Ben Stokes' Headingley heroics, now seem distant memories, and here are three key areas England must address if they are to ensure this Ashes defeat does not derail their Test side for a long stretch.

TOP-ORDER TRIBULATIONS

An elephant in the room heading into the series was England's crippling lack of options at the top of the order. Jason Roy, impressive in England's World Cup campaign, was shoehorned in alongside Rory Burns, who - with high scores of 133, 53 and 81 - has proved his worth as an opener.

Roy has failed to do so, with the aggression which serves him well in one-day cricket proving his downfall in the longest form.

After making just 57 runs from the first three Tests, Roy shifted to four at Old Trafford, switching with Joe Denly, who showed his ability to adapt with an admirable display in the second innings. Roy made 22 and 31 and was bowled twice.

The question now is whether to stick or twist with one of Roy or Denly while Ollie Pope, who scored an unbeaten 221 for Surrey in August, could be reintroduced with the view to becoming Burns' long-term partner.

ROOT GAMBLE HAS NOT PAID OFF

Given the frailties at the top of England's batting order, it was decided captain Root would bite the bullet and move up from his preferred slot at four, coming in at three instead.

It is a risk which has failed to pay dividends, with Root having been dismissed for ducks in three of the four Tests so far.

Though he played captain's knocks at both Headingley and Old Trafford, after a decent 57 in the first Test, Root does not seem comfortable coming in at three, having had less time to rally himself - not to mention the dressing room - following what has typically been the loss of an early wicket.

TWO WICKETKEEPERS, TOO MUCH

A star of limited-overs cricket, Jos Buttler's ability with the bat cannot be called into question, but the Lancashire wicketkeeper had scored over 30 only once in the series prior to the fourth Test.

Buttler perked up with 41 and 34 at Old Trafford. His ability behind the stumps has not been called upon, with Jonny Bairstow handed the gloves for the series, and it has been an underwhelming series for the former Test vice-captain.

Yorkshireman Bairstow has also struggled with the bat - scoring a high of 52 in the first innings at Lord's.

Given England's issues higher up the order, now might be time for a more streamlined approach, and one - if not both - of the keepers may have to make way, especially with Ben Foakes waiting in the wings.