“Do not raise your hands against the citizens of your own country,” he said. People interviewed in the crowd said they were certain that Mr. Ivanishvili’s party would win the election, and equally certain that the government would declare victory. Alexander Cherkezishvili, 49, said he was bracing for what would happen. “Nothing will happen on Monday, we will have elections, that’s all,” he said. “The main question is what will happen on Tuesday. If there is fraud, people will fill the streets. I personally will go out.”

The government’s pollsters are equally confident, saying that Mr. Saakashvili’s party, the United National Movement, began with a hefty lead and has rebounded from the damage inflicted by the release of the prison abuse videos last month. Giga Bokeria, Mr. Saakashvili’s national security adviser, told reporters in Tbilisi that his fears about election-related violence had subsided since then, though he said opposition leaders were stoking tensions.

“Any party raises expectations of victory, it’s normal,” Mr. Bokeria said. But, he said, pointing to a certain number “and saying that anything different from this number, like 60 percent, would automatically mean a stolen election, is also a problematic message to core supporters, and could bring up the temperature and contribute to incidents.”

Giorgi Gogia, a researcher at Human Rights Watch, said his expectations had changed markedly since two weeks ago, when he expected the United National Movement to win 55 or 60 percent of the vote. At Saturday’s demonstration, he said, the opposition crowds were “very, very confident,” and left the impression that they would take to the streets if they were unhappy with the results. “It’s the first time in 20 years of Georgia’s history that we actually don’t know the outcome of the elections,” he said. “This is the first time when the opposition also has the resources to galvanize people.”