1) Pitches

When Australia's coaches and selectors peered down at the Trent Bridge surface for what seemed like forever on the first morning, their scepticism was clear. A similar scene had taken place at Edgbaston. On both occasions Australia wound up batting, though on the second they were sent in to do so. The team's subsequent inability to cope with seaming, swinging English conditions would define their two heavy defeats and undo all the good work done on a less helpful surface at Lord's. All series it was apparent that Australia expected a repeat of the sort of dry surfaces glimpsed in 2013, but it was clear this would not be the case once a low, slow Cardiff pitch posed more problems for Australia's batsmen and bowlers than it should have done. England's captain Alastair Cook and coach Trevor Bayliss asked for pitches that would accentuate their team's powers of swing and seam, and in helpful climes at Edgbaston and Trent Bridge they got them. Having dominated at Lord's, Australia's batsmen failed utterly to make the requisite adjustment.

2) Hubris

"I can't wait to get over there and play another Ashes against England in their conditions after beating them so convincingly in Australia. It's going to be nice to go in their backyard. If we continue to play the way we have been playing over the last 12-18 months, I don't think that they'll come close to us to be honest." That was Steve Smith's oft-quoted view of this series, stated to ESPNcricinfo while in India for the IPL. There was a sense of hubris about Australia all the way through the tour, even to the extent that the players refused to admit the jig was up when facing near impossible circumstances in Cardiff, Birmingham and Nottingham. Confidence runs deep in this Australian team, and at their best in Australia they have every reason to believe in it. But the hype should not extend to difficult assignments anywhere overseas other than South Africa. This was never more evident than in the bowling selections, where Peter Siddle's strong record in England was ignored in favour of Josh Hazlewood and Mitchell Starc alongside Mitchell Johnson. The loss of Harris before the series was a grievous blow, but the selectors stuck doggedly to the view that Starc, Hazlewood and Johnson could blast England out, even after it was readily apparent that a cannier operator was required.

3) England

Just as Australia were able to wrong-foot England by replacing Mickey Arthur with Darren Lehmann in 2013, the reverse was true this year as the ECB appointed Trevor Bayliss to take over from Peter Moores. The bold, abrasive approach favoured by Lehmann had worked beautifully when pitted against the more attritional styles of Andy Flower and Moores, most recently when England were battered in the opening match of the World Cup. But an evolving captain in Alastair Cook, a smiling but savvy coaching duo in Bayliss and Paul Farbrace and a demonstrably younger team rounded out by the most experienced new ball duo in world cricket found a formula that appropriated Australian aggression but also added English knowhow in these parts. Bayliss made one misstep in talking up Australia's fightback powers after Cardiff, but he learned quickly to concentrate on moulding his team. It was hardly the first time that the younger, emerging Ashes team had overcome their elders.

4) Clarke and Smith

At Nos. 3 and 4, Smith and Clarke were the critical pivots in the Australian batting order, either carrying on from the early good work of the openers Chris Rogers and David Warner or forming a bulwark against the new ball should the top two be separated early on. In four first innings this series, only Smith at Lord's was able to make the sorts of scores expected of him, while Clarke's decline as a batsman was so marked that he could not get past 38, a score he managed in his first innings of the series. Clarke tried every method to get himself going, spending endless hours in training and alternating between aggressive and conservative starts. At Trent Bridge he even batted in his past No. 5 position. But Clarke's failure to find his work led ultimately to the admission of retirement, something also brought about by the failure of others around him. Smith will wonder at the mental challenge of the Ashes, something that not only had his trigger movement across the crease getting more exaggerated each time, while his earlier commitment to play watchfully until set was forgotten in a flurry of nervous shots in Nottingham. Australia could not win this series without runs from both Clarke and Smith, and they didn't.

5) Allrounders

Not since 2005 has an England allrounder contributed as much to an Ashes series win as Ben Stokes, something the captain Cook had accurately predicted beforehand. By contrast, Australia burned through both Shane Watson and Mitchell Marsh over the first three Tests, and at Trent Bridge abandoned a long-held belief that five bowlers were a critical component of the team's balance. Watson may never play another Test match, and Marsh has plenty of learning to do before he can become the finished article. A stint in the English county game - something Marsh tried to achieve last year but could not secure a contract - would not go amiss. Having had a chastening experience of Ashes defeat in 2015, Marsh may well be ready to be a more dominant performer next time around, much as Stokes learned from his promising showings in 2013-14 to be a major player this time.