"We are not complacent, and we will never rest on our laurels," Xi said
China's all-powerful Communist Party on Thursday unveiled a new seven-man leadership council steered by Xi Jinping to take command of the world's number two economy for the next decade.
After striding out in Beijing's Great Hall of the People as the party's new general-secretary, succeeding President Hu Jintao, Xi vowed to fight official corruption and build a "better life" for the nation's 1.3 billion people.
Xi's long-expected ascent to the apex of national politics was confirmed when he emerged onto the stage in front of the other six members of the elite Politburo Standing Committee, after a week-long party congress.
Xi, 59, has an impeccable political pedigree as the son of a lieutenant to revolutionary leader Mao Zedong. He will formally replace Hu as state president when the rubber-stamp legislature confirms the appointment in March.
"We are not complacent, and we will never rest on our laurels," Xi said in his first address to the nation, standing in front of his colleagues on the new committee -- all men, who all bar one wore red ties.
The new committee has been slimmed from nine members to seven, a change analysts said would ease decision-making at the consensus-driven heights of the Communist Party as as China faces rapid change on a host of fronts.
"Under the new conditions, our party faces many severe challenges, and there are also many pressing problems within the party that need to be resolved," Xi said, highlighting graft and alienation from citizens.
"We must make every effort to solve these problems. The whole party must stay on full alert."
Xi appeared confident and far more relaxed than his stiff predecessor Hu, starting out with a disarming apology for the speech's late start and then talking about ordinary people in plain language.
Some users of the nation's popular Twitter-like microblogs welcomed the speech, with its lack of Communist jargon or mention of socialist heroes, as a refreshing departure.
"I hope the new crop of leaders will not disappoint the people's hopes, will innovate and reform, and courageously strive to create a democratic and constitutional new nation," wrote one user.
Xi's standing at the top of China's opaque power structure was consolidated with his appointment as chief of the nation's vast military as head of the Central Military Commission.
Hu's predecessor Jiang Zemin had clung on to that job for two years after relinquishing the presidency, preventing him from taking full control of China.
In second place in the new Politburo Standing Committee was current Vice Premier Li Keqiang, whose promotion puts him in line to be appointed premier in charge of the nation's day-to-day economic administration in March.
The spectacle marked the climax of years of jockeying within the secretive party, which brooks little dissent to its monopoly on political power but which has had to take new account of the public's demands in the age of social media.
Analysts said that despite calls from Xi, Hu and others for reform, the new leadership line-up appeared to have a conservative slant, but also stressed that continuity and stability reigned supreme in the communist system.
"I think that this is the result of compromise and consensus among different groups," Chinese University of Hong Kong associate professor Tsao King Kwun said.
The process was essentially finalised Wednesday when the party ended its week-long congress by announcing a new 200-strong Central Committee.
The seven men who hold innermost power are tasked with addressing a rare deceleration of economic growth that threatens the party's key claim to legitimacy -- continually improving the livelihoods of the country's people.
China also bubbles with localised unrest sparked by public rage at corruption, official abuses, and the myriad manifestations of anger among the millions left out of the country's economic boom.
On Thursday, just as Xi was being unveiled before the nation, another Tibetan self-immolated in a remote region of the Tibetan plateau, state media said. About 70 Tibetans have set themselves alight in protest over Chinese rule over the last year.
China's economy, which relies heavily on manufactured exports and heavy infrastructure investment, has been stunningly successful in lifting hundreds of millions out of poverty.
But the party acknowledges the model is becoming unsustainable as the economy matures and demands for higher living standards grow, and Hu last week called for a new approach with a robust private sector and stronger domestic demand.
How the new leadership under Xi will address these challenges in the world's most populous nation remains unclear.
"Everything will depend on Xi Jinping and whether he exercises leadership. Will he be someone who can introduce reforms? I'm still very sceptical," said Jean-Pierre Cabestan, an expert on Chinese politics at Hong Kong Baptist University.
The run-up to this year's congress was unsettled by events surrounding former rising star Bo Xilai, who was brought low by scandal, and by new allegations about secret riches amassed by the families of top leaders.