He said: "I will always defend our people and our existence in Kosovo. The state should always take care of its people."
Albanian message
The pro-Western leader told a gathering of the ethnically mixed village's 195 Serbs, who live on one street, that "these days we are deciding the fate of Serbia and the citizens in central Serbia should know that they are also deciding about Kosovo".
Seeking to pull back some votes from his nationalist rival, Tadic said: "I will never accept the independence of Kosovo and I will never push our country into war. To the Albanians, we give the message that we want good relations with them."
Tadic is due to attend an election rally at a square in central Belgrade later on Thursday.
Nikolic's Radical Party plan to stage a five-hour rally that ends at midnight (2300 GMT), when official campaigning ends.
The two clashed in a televised debate late on Wednesday in which Tadic portrayed the vote as a referendum on Serbia's integration with the EU.
In the duel, Nikolic, 55, taunted Tadic throughout as "Mr former president" and the "regime candidate," and promised to unite a country "tired of awaiting better days."
If Tadic wins, he will have to do it without the backing of Vojislav Kostunica, the conservative nationalist prime minister, who refused to endorse his coalition partner because he rejected a tough line against the EU's Kosovo policy.
Unilateral declaration
Kosovo has been run by the United Nations since 1999, when Nato bombing drove out Belgrade-controlled forces waging a brutal crackdown on separatist Albanians who form around 90 per cent of its two million population.
Many Serbs have since fled Kosovo fearing reprisal attacks and most of the estimated 100,000 who remain live in small enclaves.
Thursday's symbolic visit by Tadic, who pledges speedy integration with the European Union, was timed to secure votes from an electorate sharply divided over the future of the country.
Hashim Thaci, Kosovo's prime minister, said on Wednesday that the province's ethnic Albanian leaders would make a unilateral declaration of independence within days of the Serbian election, regardless of who wins.
Along with the United States, most EU member nations are ready to recognise such a proclamation.
The latest opinion polls give Tadic a narrow advantage, but a large slice of the troubled Balkan country's 6.7 million electorate remains undecided, pollsters say.