It was supposed to be a new era. Instead, it was another overseas Test series defeat for England.

There were promising signs in the second Test in Hamilton but Joe Root's side were thwarted on the final day as New Zealand held out for a draw to take the two-match series 1-0.

Root returned to form with a double century and England's inexperienced batting line-up showed potential, but there remains plenty of questions.

What did we learn from defeat in New Zealand - and what problems still need solving?

England can bat big after all

Without a first-innings total of 400 since 2017 and bowled out in a session four times in three years playing "positive cricket" - all eyes were on England's new approach with the bat in this series.

Things went horribly wrong as they were thrashed by an innings and 65 runs in the first Test, but they responded admirably by posting 476 in the second.

Root made 226 and opener Rory Burns 101 - the first time England have had two centurions in the first innings since September 2018. Their partnership of 175 was England's first of 150 or more since Alastair Cook retired last summer.

England batted for 162.5 overs at Seddon Park, their longest innings for fours years, while 21-year-old Ollie Pope hit his maiden Test half century, underlining why he is regarded as one of the most highly rated young batsmen in the country.

Who knows...? England may well have passed 500 had they not been chasing quick runs, with one eye on the weather forecast.

Root can score hundreds as captain

Root's 441-ball innings was his longest in Tests

The scrutiny around Root's batting form as captain had never been greater than before the second Test.

He managed only two and 11 in the first Test, taking his average to 39.70 since taking charge, compared with 52.80 beforehand.

But in Hamilton he responded in the best possible fashion by scoring his third Test double hundred. It was his highest score as skipper.

It may have come on an extremely flat pitch, but Root's sixth score of 100 or more since succeeding Alastair Cook will quieten the doubters for now.

New Zealand are just better than England

It would be hard to argue England deserved much more than they got from the series, given the balance of play across all 10 days.

The statistics show New Zealand have a better batting line-up and, in the first Test, they showed they have a bowling line-up capable of taking wickets in unfavourable conditions.

The Black Caps' success should come as little surprise.

They are second in the International Cricket Council rankings, a place above England, and are now unbeaten in seven Test series.

Kane Williamson's side have six batsmen who average more than 40 in Tests. Only Joe Root among England's batsmen averages more than 36.

Australia and India, New Zealand's next opponents, are likely to be provide a much sterner test than England did.

Are England any closer to finding an opening partnership?

Dom Sibley was doing his GCSEs the last time England had a settled opening partnership, in the form of Cook and Andrew Strauss.

The Warwickshire batsman was the latest in a long line to be given a go for this series, thanks to an average of almost 70 in the County Championship this summer.

Fellow opener Burns enhanced his reputation, backing up a solid Ashes campaign with a series average of 61.33 and a second Test century. He has solidified his place as one of England's openers.

Sibley, though, had a difficult first taste of Test cricket.

He scored a promising 22 in his debut innings but made only 16 runs combined in the following two innings and looked limited in his scoring areas.

The 24-year-old was also hit on the head twice - in the warm-up game and in the second Test - and looked uncertain against the short ball at times.

South Africa's pace bowlers will have taken note.

• A hip hop fan who is hopeless with a vacuum - who is Sibley?

How can England take wickets on flat pitches?

England's bowlers failed to take 20 wickets in either match of the series and have done so only five times in 20 away Tests since 2016.

It was hoped Jofra Archer would bring added potency to the attack on flat pitches, but he managed only two wickets in the series, albeit on his first overseas tour.

Archer took two wickets at an average of 104.50 in the series

Stuart Broad was far less effective than in his stellar Ashes campaign this summer and Sam Curran is yet to prove he can be a potent third seamer when the ball does not swing.

Questions also remain regarding Jack Leach's place as the team's frontline spinner after he was dropped for the second Test.

All-time leading wicket-taker James Anderson is likely to return in South Africa, where the pitches should offer greater assistance for seamers.

However, with a tour to India next winter, and the Ashes in Australia in 2020-21, the task will only get tougher for England's bowlers.

Is Root the right man as captain?

Even before Root's return to form with the bat, few would suggest he should be dropped. After all, England have never lost a Test when he has scored a hundred.

However, some critics question whether he is a good enough tactician to lead England.

Some of his decisions in the field were questioned during this series, notably bowling Archer - England's youngest and quickest bowler - for 42 overs in the first Test.

Under Root's watch, England failed to win a Test series in 2019, the first time they have failed to do so in a calendar year for 20 years.

He has a win percentage as captain of 49% - only two men to have led England in as many matches as Root's 36 can better that - but he has a high loss percentage too (40%), the highest of those to have captained as many matches.

England's director of cricket Ashley Giles has backed Root to carry on until the next Ashes series in two years' time.

If not Root, then who else? That's a debate for another day.