The Ashes: Three key battles

World Cup winners England are switching their focus to regaining the Ashes, with Australia desperate to beat their oldest enemy away from home for the first time since 2001.

AFP Sport looks at three key battles in the five-Test series that starts at Edgbaston on Thursday:

Warner v Roy

Both England and Australia have batsmen at the top of the order with the ability to dictate the pace of an innings and with something to prove.

Australia's David Warner, who had an impressive World Cup campaign, is resuming his Test career after serving a ban for his part in last year's ball-tampering scandal in South Africa.

Warner, 32, who has scored 21 Test centuries, has the knack of quickly taking the game away from the opposition and England will be desperate to get him early.

Jason Roy, 29, has played a single Test, against Ireland last week, after 84 one-day internationals for England and will be keen to show he can bring his swashbuckling style into the Test arena.

But Australia paceman Josh Hazlewood has warned him that Test cricket is a different ball game from the frenetic limited-overs format.

"We'll see how Roy goes in Test cricket," said Hazlewood. "He has only played one Test match and it's a lot different opening the batting in a Test than a one-day game, that's for sure."

Smith v Root

When Australia and England last met, in Australia in 2017-18, Steve Smith and Joe Root were the opposing skippers.

Since then, Smith has been stripped of the captaincy and he is preparing for his first Test outing since being banned over last year's ball-tampering incident.

Smith, like Warner subjected to some rough treatment from the English crowds during the World Cup, will feel he has something to prove.

Averaging an eye-catching 61.37 in 64 Tests, with 23 centuries, Smith is still the main man for Australia and he scored a total of 687 runs when the teams last met, hitting three centuries in five Tests.

Root's Test average has dipped below 50 but he remains one of most feared players in the game and England's finest batsmen, with 16 Test centuries under his belt.

The Yorkshireman is moving back up to number three to boost England's struggling top order.

Since Root dropped a place during the India series last year, several options have been tried, including Moeen Ali, Jonny Bairstow and Joe Denly.

But none has settled the debate and now Root is ready to return to a position from which he scored his Test-best 254 against Pakistan in 2016.

English guile v Australian pace

England have a new weapon in paceman Jofra Archer but the key to their Ashes bowling attack will be veteran opening bowlers James Anderson and Stuart Broad.

Anderson and Broad, with more than 1,000 Test wickets between them, lack the sheer pace to frighten batsmen but are masters of exploiting English conditions with swing.

Australia, on the other hand, have a battery of fast bowlers who could inflict real damage on England's fragile top-order.

"Australia have bowlers who can blast you away -- Pat Cummins, Mitchell Starc, James Pattinson and Josh Hazlewood," said former England paceman Steve Harmison.

"But if they don't get it quite right they can go at six an over. Broad and Anderson will very rarely go at six an over.

"They'll be down on pace compared to the opposition, but they'll have total control of what they're doing."