UPDATE 1-Egypt's Brotherhood flexes muscles in push for presidency
* Brotherhood's Mursi was latecomer to campaign
* Rivals include other Islamists, men who served Mubarak
* Brotherhood built up support through social work (Recasts, changes dateline, bylines)
CAIRO, May 20 (Reuters) - Egypt's Muslim Brotherhood showed off its ability to rally support with choreographed campaign events throughout the nation on Sunday in a final push to clinch victory for its candidate in this week's presidential election.
Well-known Islamic preachers and soccer celebrities took to the podium in Cairo to endorse Brotherhood candidate Mohamed Mursi, a relative latecomer to the race. His main rivals include Islamists and ex-officials of former President Hosni Mubarak.
With official campaigning ending on Sunday, fireworks cracked in the night air and flames flared from the front of the stage as Mursi arrived to address the audience of several thousand gathered in central Cairo, outside Abdeen palace.
One poll published last week in al-Masry al-Youm newspaper put Mursi behind three other front-runners but also said 37 percent of those surveyed had not made up their minds.
The reliability of such polls are untested in a nation that until Mubarak was ousted by a popular uprising in February last year had not had a free election for decades. The large cohort of undecided voters also makes it difficult to pick a winner.
But Mursi has the backing of the Brotherhood's broad grass-roots network of supporters which proved its ability to get out the vote when it won the biggest bloc in a recent parliamentary poll.
Youths wearing Mursi t-shirts gathered at the front chanting "Mursi, Mursi" to the beat of drums. "God willing, Mursi will be president after the first round," they chanted,
The election that starts on Wednesday is the last stage in a messy transition to democracy, overseen by generals who took control after Mubarak was driven out and have pledged to hand power to a new president by July 1.
Other candidates were also chasing votes on Sunday, doing last-minute TV interviews, holding final campaign news conferences and having their supporters take to the streets.
But the Brotherhood planned the slickest routine, with simultaneous rallies hosted in 25 locations across the nation.
Listing places around Egypt, Mursi told the Cairo crowd: "We will take a serious step towards a better future, God willing."
He promised to combat any corrupt hangers-on from Mubarak's era. "If they take a step to take us backwards, to forge the will (of the people) and fiddle with security, we know who they are," he said. "We will throw them in the rubbish bin of history."
Mursi was pitched into the race as the Brotherhood's reserve candidate when its first choice was disqualified. Critics see Mursi as a dull functionary who lacks the spark of leadership.
Mohamed Abdel Maqsoud, a Salafi preacher, one of those on stage to endorse Mursi, made light of his reserve status, saying that no one went on a trip without a "spare tyre" and substitutes could win soccer matches.
Victory for Mursi would give it both executive and legislative power and consolidate a dramatic resurgence after decades of suppression by a succession of military strongmen. It would also confirm a trend of growing Islamist power at the ballot box since a wave of Arab uprisings began last year.
Maqsoud said Egypt should follow the example of Turkey, where the presidency and parliament were controlled by one party and where the influence of the army had been gradually rolled back. Many expect Egypt's army to remain influent for years.
Although the Brotherhood now dominates parliament, it has achieved little influence over an army-backed government still struggling with the turmoil sparked by Mubarak's overthrow.
But it can still draw on a base of support built up from years of social work, even during the decades when it was banned by Mubarak. In Nile Delta towns, hit by an economic crisis since Mubarak's fall, that has helped win over voters.
"God willing, I will vote for them and most people in the town will do so as well. No one served us better than the Brotherhood," said Ahmed Youssef, a 41-year-old employee in a state telephone office in the large Delta town of Tanta.
"My dear friend here will do the same, won't you?" he said, turning to a 40-year-old street trader, Mohamed Sherif al-Din.
"Mursi is a Brotherhood man and this group is the one that hires our kids and brings us goods that we don't find in the market. God bless them and him," said Sherif al-Din, who was cycling around the Delta town of Tanta handing out Mursi flyers.
Widespread illiteracy and deep scepticism bred by three decades of managed politics under Mubarak make it hard to win over voters by setting out manifestos of policy promises.
In the first post-Mubarak parliamentary vote, spread over from November to January, Islamists won more than two thirds of seats, with the Brotherhood taking the biggest share.
Liberal parties that lost out blamed their failure partly on a lack of reach compared to the Islamists, who used mosques and religious charity networks to canvas the electorate.
Brotherhood activists say criticism over the failure of the Islamist-dominated parliament to exert any sway over the government in recent months has little impact on most voters.
"Religion is in the blood of people and not everyone is exposed to media, so its voice isn't heard," said Ismail Farouk, a Mursi campaigner in the southern town of Sohag.
In Sohag and elsewhere, the Brotherhood is touting local initiatives as part of its national "renaissance project" to win over voters angry at years of neglect by the government in Cairo.
Brotherhood campaigners play up Mursi's appeal as its anointed choice to lead Egypt, in contrast to another Islamist, Abdel Moneim Abol Fotouh, who was ejected from the Brotherhood last year and is seen as a front-runner for the presidency.
Abol Fotouh is pitching to voters across the spectrum, from ultraconservative Salafis to moderate Islamists and liberals. The Brotherhood is selling Mursi as the authentic religious conservative.
In Cairo, advertisements for Mursi show him in a short beard accompanied by the slogan: "Renaissance comes through the will of the people", with no mention of Islam.
Mursi banners in the industrial and agricultural Delta region north of Cairo show his beard whiter and much longer to suggest great piety. The dominant slogan changes to "Egypt's renaissance with an Islamic foundation".
A Brotherhood strategist in Cairo, Mostafa Abdel Ghafar, played down the criticism of Mursi's leadership talents.
"I think all people noticed that our campaign is not for Mursi as a person, but for the group's renaissance project, which Egyptians have heard about for a year," he said.
But the headwinds for the Brotherhood seem stronger than before the parliamentary election, when its long struggle against a monolithic Mubarak establishment finally paid off.
"There is no way I would vote for the Muslim Brotherhood in the presidential vote, as so far they have brought us nothing but chaos," said Ahmed Rafaie, a 32-year-old employee in Tanta.
"They might have got many votes in the parliament, but this won't happen again." (Additional reporting by Tamim Elyan and Yasmine Saleh; Writing by Edmund Blair and Tom Pfeiffer; Editing by Alistair Lyon and Paul Simao)