Out-going Conservative leader Michael Howard has urged the party to unite and support whoever succeeds him.
Mr Howard did not endorse any candidate but said their performances marked "a sea-change in the mood in the party", as he closed the Blackpool conference.
He told the BBC the gamble of turning the annual gathering into a leadership "beauty contest" had paid off.
David Davis had earlier insisted he was still "odds on" to be next Tory leader despite press criticism of his speech.
'Don't be offensive'
The Conservative conference in Blackpool was transformed into a forum for leadership pitches by Mr Howard's announcement after the election defeat in May that he would stand down.
Mr Davis and fellow contenders David Cameron, Kenneth Clarke, Liam Fox and Sir Malcolm Rifkind all had 20 minute spots to woo Conservative activists.
Mr Howard told the BBC the whole week "could have gone pear shaped", but said the gamble had paid off.
In his final speech as leader Mr Howard urged Tories to stick to their "timeless values" but to adapt them to "the world as it is".
He said: "Of course we need discussion and debate. But let's not be offensive about each other.
"Let's not run down our party. Let's show we can elect a new leader without bitterness and backbiting."
He said the party had to be "clear, confident and consistent" to win the next election.
He added: "In 1979 we won more support among young people than in the electorate overall."
"Not by trying to be hip and cool, but by showing that we understood young people's aspirations.
"They wanted a Britain where they would have more freedom, more opportunity and more power to better themselves, their families and their communities."
There was no "natural party of government", he said, adding: "The right to govern is a privilege we have to earn."
He added: "Unity and discipline are essential. And I promise you this: whoever you choose to succeed me I shall support to the utmost of my ability."
Mr Howard's speech came against a background of feverish debate about the performances of the various the leadership contenders.
Mr Davis' speech was the biggest disappointment of the week, according to the newspapers and rival leadership contender, Sir Malcolm Rifkind, said: "He must be very, very worried because he was speaking to a party of Conservative enthusiasts who wanted to will him to succeed.
"If he was unable to achieve that one has to ask the question how would he deal with Gordon Brown over the next four years."
However, Mr Davis said he was still "odds-on favourite" to become leader and that he would face "tougher tests" in future.
BBC political editor Nick Robinson said the shadow home secretary was "fighting to stay the favourite" in the contest, amid "real doubts" among the membership.
Party chairman Francis Maude said the conference had been "brilliant" and that Conservatives must "not slip back into a cosy comfort zone where we congratulate ourselves in ever smaller rooms about the excellence of our policies while too many modern Britons blithely ignore us".