Australia's overseas challenge

The 2013 Ashes series was won 3-0 by England; a few months later, they went to Australia and got hammered 5-0. Combine the two series, and we get a unique sequence in Ashes history - never before has the overseas team failed to win a Test in two successive Ashes series of five or more Tests. There was one instance of such a barren sequence for the overseas team, but one of those series was of three Tests: in 1912, England won a three-Test Ashes series 1-0 (that was the season of the triangular tournament, with South Africa being the third team, but the Tests between England and Australia were still played for the Ashes), and in the next series played between them, after World War I, Australia won 5-0 at home in 1920-21. Since then, there has never been two successive Ashes series in which the overseas team hasn't won at least one Test. (Click here for a list of Ashes series since June 1912.)

England will hope that sequence continues over the next couple of months, but they won't be going into the series as favourites. Australia have been the form team over the last one-and-a-half years: since November 2013, they have won 11 out of 16 Tests, losing only three. Out of five series, they've won four - against England, South Africa, India and West Indies, losing only to Pakistan in the UAE. England, on the other hand, have a 5-9 record in 17 Tests during this period, winning only one series out of five. Australia's win-loss ratio of 3.66 is the best during this period; England's ratio of 0.55 is seventh out of ten teams - only India, West Indies and Zimbabwe have done worse.

During this period, Australia's batting has notched up much better numbers than their England counterparts, but the difference in bowling stats isn't as much: Australia's batting average is about 25% better than England's but their bowling average is only about 9% better. The difference, among the batsmen, has largely been the openers, though Alastair Cook's recent form against New Zealand is excellent news for England, and suggests the difference between the two teams might not be as much as those numbers indicate.

For Australia, David Warner (average 59.03, nine hundreds in 32 innings since November 2013) and Steven Smith (75.91, eight hundreds in 30 innings) have been the form players, while Chris Rogers (1149 runs at 41.03) and Michael Clarke (855 runs at 40.71) have been key contributors as well. England have banked on the incredible talent and consistency of Joe Root (1510 runs at 65.65), while Cook has returned to form as well, but there are question-marks over Ian Bell (867 runs at 29.89 in his last 30 innings), while Gary Ballance hasn't been entirely convincing despite averaging 52.19 in 23 innings.

The difference in bowling numbers isn't so stark, and the gulf is even lesser now with the withdrawal, and retirement, of Ryan Harris. Mitchell Johnson has been Australia's number one strike bowler by far, with 86 wickets in 15 Tests at 19.60, but in Harris' absence the others will need to step up consistently if Australia are to stay ahead of England. For the home team, the Dukes ball and familiarity of conditions will surely help James Anderson and Stuart Broad, both of whom have averaged less than 28 in the last 20 months.

Australia's recent problems in England
Australia's problem over the last decade, though, has been winning Test matches in England: in their last three Ashes campaigns overseas, they've won two Tests and lost seven. (They lost by identical 2-1 margins in 2005 and 2009, and 3-0 in 2013.)

However, you wouldn't know that looking at their overall batting and bowling stats in these 15 Tests: they've averaged 33.85 runs per wicket with the bat, and 33.15 with the ball. You'd expect a team that has lost three times as much as they've won to have a much higher bowling average than the batting one, but Australia have lost several close Tests, while their two wins were by huge margins. At Lord's in 2005 they won by 239 runs, while at Headingley in 2009 their victory margin was an innings and 80 runs; three of their seven defeats were by two runs, three wickets, and 14 runs. (Click here for the results in the 15 Ashes Tests in England since 2005.)

Australia's current captain, Michael Clarke, has played each of those 15 Tests, averaging a healthy 48.50, while Shane Watson and Chris Rogers average more than 40 too, and Smith 38.33. Warner has struggled a bit, but has played only three Tests in England.

None of the Australian bowlers in the current squad average less than 30 in England, though there are several who average in the early 30s. Harris had a fantastic series in 2013, taking 24 wickets in four Tests at 19.58, but he isn't around this time, which means more responsibility on the rest of the bowlers. Watson is expected to shoulder some of the additional burden in Harris' absence, but his record in England isn't encouraging - two wickets in eight Tests at an average of 114.

Johnson v England's batsmen
With Harris absent, there will probably be more pressure on Johnson to be the strike bowler and continue from where he left off in the 2013-14 Ashes. Johnson has an outstanding record against Bell in England, but not so much in Australia. Cook, on the other hand, averages 42 against Johnson in Australia and 22 in England, but he too struggled against Johnson in the 2013-14 series, scoring 73 and being dismissed four times; in the 2010-11 Ashes, he scored 139 runs for one dismissal. The one player who would do well to remember his stats against Johnson in England is Stuart Broad: 72 runs off 82 balls, with one dismissal. Johnson, though, will quickly want to remind him of what happened in the most recent Ashes series.