Many of his challengers, including a former prime minister he sacked two years ago, Idriss Seck, 47, have said only electoral fraud would make it possible for him to win in the first round.
Even before the official closing time of polls, Wade supporters had driven around the streets of the capital blowing car and motorcycle horns in celebration.
If Wade proclaims victory, "the people will not accept that," said Khalifa Tall, campaign manager for Ousmane Tanor Dieng, candidate of the Socialist party which ruled Senegal for 40 years after the country gained independence.
"We are still planning for a second round," he said, raising fears of trouble.
Private radios streaming unofficial results as they were counted at polling stations, said that with 35 per cent of ballots counted, Wade had obtained 53 per cent of the ballots.
Voters thronged polling stations Sunday in the polls which are being seen by some as a test case of the country's long-held reputation of democracy.
Polling was extended by several hours due to late delivery of polling materials in some areas and a massive voter turn-out at some of the more than 11,000 polling stations scattered across the predominantly Muslim country.
Sall estimated turn-out at a record 70 per cent.
Wade said he was confident he would beat a record 14 challengers and achieve the decisive 50 per cent of the ballots needed to avoid a run-off round of voting.
"There will not be a second round, I will win," he said after he cast his vote in Dakar.