Senegal's ruling coalition candidate Amadou Ba has called the opposition's Bassirou Diomaye Faye to concede victory in Sunday's presidential elections, a government official said.
Unofficial results showed that Mr Faye had a strong lead over Mr Ba.
Mr Faye had been in prison 10 days before the vote and campaigned on the promise of radical change.
Official results are expected in the coming days from the election which was originally due last month.
The vote followed months of political turmoil in one of Africa's most stable democracies, after outgoing President Macky Sall tried to postpone the election until December.
Several of the other 15 candidates had already conceded to him.
President Sall has also congratulated Mr Faye and said that it was a win for the people of Senegal.