Bill English has faced many battles in his long political career but nothing like the uncertain election he faces in the next eight months to lead National to a fourth-term victory.
It is the fight of his life and in some ways it is John Key's as well.
Earning the title of Prime Minister rather than inheriting it from Key it will be a strong motivation.
If English wins, it will not just be redemption from his failed leadership of another era, it will also validate Key's decision to quit.
It would turn what was possibly a reckless or selfish departure into an act of unparalleled foresight and courage.
The first thing English must do is to introduce himself and his family to the voting public in ways that reveal values, character and humour they can connect with.
The odd tweet at Christmas showed the English clan enjoying a game of backyard cricket under the pohutukawa of Karori.
But despite his 26 years as an MP, English has been a relative stranger except to pockets such as the Dipton stockyards, the Wellington beltway, company boardrooms, and the English clan.
As an ex-leader and then Finance Minister, it was his duty to lie low, be steady, boring and non-controversial. That will change, and fast.
English has promised to start revealing more of himself today in his state of the nation speech in Auckland.
John Key was an open book, with a willingness to share his life from cats called Moonbeam to vasectomies.
English is more strait-laced and is likely to be more constrained.
The second thing English must try to do is stop comparisons between himself and Key. To do that English must be bold and sharp all the time, as he was in his press conference when he was elected, as he was yesterday, especially in his attacks on Labour and the Greens.
He ridiculed the "vibe" of their increasingly close association, a theme that will resonate for the next eight months as he suggests they are not fit to govern.
New Zealand First were deemed more fit to govern as potential coalition partners for National in English's ranking but the preferred partners were the current ones: Act, United future and the Maori Party.
English's credentials in steering the economy through the global financial crisis to surplus and relative stability will be a strong basis for National's campaign.
But it will be held in a new era of global uncertainty and unpredictability. It is not yet clear how isolated New Zealand will be.
If Kim Dotcom and the Internet Party was the wild card in the 2014 election, Gareth Morgan's Opportunities Party looks set to take that role in 2017.
As Geoff Simmons, the party's Mt Albert byelection candidate said yesterday, if 2016 and Monday's result at Mt Eden Park showed "there is no such thing as a foregone conclusion."
'Everything is up for grabs'
● Winning a fourth term has happened only twice since World War II: the Labour Government of 1935, 1938, 1943 and 1946; and the National Government of 1960, 1963, 1966 and 1969.
FOUR CRUCIAL FACTORS IN WINNING THE ELECTION:
● LEADERSHIP: Bill English has to quickly establish his own style of leadership. He should not draw on John Key's any more than Andrew Little should draw on David Cunliffe's.
● HOUSING: Even with house values cooling, housing affordability will continue to be one of the most important issues, especially for young voters. But the possibility of rising interest rates this year may exacerbate the problem for those with mortgages.
● THE BUDGET Low and middle-income families will be front and centre of the May Budget, which will be the platform for the Government to address inequality. Labour's alternatives can't break the bank.
● WINSTON PETERS: The insurance policy: NZ First leader may decide the next Government. Handle with care: He should not be mollycoddled but he shouldn't be alienated.