Chants rang out around Luzhniki stadium in Moscow: "Putin! Putin! Putin!", which gave way to "The people! Medvedev! Putin!" and then "Russia! Russia! Russia!"

Delegates from the ruling United Russia party dutifully applauded while youth activists, bussed in from the provinces, waved bulky flags for two hours straight.

But one man was not happy. "When you scream 'Putin! Medvedev!' that's well enough," Vladimir Putin called out from the podium as he officially accepted his party's nomination for a presidential election that he is all but assured of winning. "But when you say 'Russia!' the whole room should shout," he ordered.

A great roar rose up as Putin loudly banged the podium in time to his subjects' obedient chants.

After four years as prime minister, a role he took up because of a constitutional ban on any individual serving more than two consecutive terms as president, Putin is not just returning to the Kremlin.

He is embracing a neo-Soviet cult of personality that has transformed from publicity stunts showing off his physique and prowess to all-out adoration intent on proving that no other leader is fit to run Russia.

The United Russia congress on Sunday was the final step in a months-long process to add a veneer of legitimacy to Putin's candidacy in the presidential vote on 4 March.

The highly orchestrated meeting – complete with United Russia members in the stands instructing people when to chant – brought back Soviet memories for many.

"Look at what's happening – it already looks like one of the Soviet Union's last Communist party congresses," Yevgeny Gontmakher, a prominent economist, said during a roundtable debate on Dozhd, a liberal cable TV channel.

The congress kicked off with speeches in support of Putin from people representing sectors of Russian society: a film director, a businessman, a pensioner, an official in Russia's feared Federal Security Service and, finally, a mother of 19.

"Russia needs a brave, strong, smart and able leader, not just to protect citizens' rights and freedoms but to remind them of their responsibilities," said Stanislav Govorukhin, the director. "We have such a person – Vladimir Vladimirovich Putin.

"He understands that the greatest task before the country and its leadership is to strengthen the soul of the people," Govorukhin said. "That's why he is my candidate."

The last time Putin appeared in a stadium, to attend a martial arts fight, he was booed and whistled, the first public show of growing discontent with his rule.

The election is likely to put Putin in the Kremlin for six years at least, and were he to win a subsequent term he could stay there until 2024. That prospect has begun to grate with the public, polls show. The most recent, by the independent Levada Centre, put Putin's support at 35%.

Putin stuck to tried and tested means of addressing critics' concerns in his speech to the thousands of delegates gathered in the stadium. Change was happening but not as quickly as it should, he said. At least life was better today than in the chaotic 1990s, he argued.

As for the opposition, they were on the payroll of the west: "We know that representatives of some countries meet with those whom they pay money – so-called grants – and give them instructions and guidance for the 'work' they need to do to influence the election campaign in our country. It's a wasted effort, like throwing money to the wind," he said to applause.

Both Putin and Dmitry Medvedev, the outgoing president, urged people to vote for United Russia in next Sunday's parliamentary election. Support for the party has fallen dramatically and pollsters have begun to predict it could lose its majority.

"No matter where you are or who you are, hear me now," a stern Medvedev said. "Remember that together we went along this path, raised the country from her knees, worked together, lived through difficulties, protected our fatherland … We are required to continue our joint work.

"Come to the elections on 4 December and vote for United Russia." He closed by saying: "We'll figure it out."