Alex Maskey's term as Belfast's first ever Sinn Féin Mayor was coming to an end today.
Belfast city councillors were due to choose a successor to the south Belfast republican.
The vote was expected to be tight, with the cross-community Alliance Party's three councillors likely to play a key role again in deciding whether a nationalist or a unionist will occupy the city's top post.
Nationalist SDLP councillor Mr Martin Morgan was the early favourite to succeed Mr Maskey because of unionist divisions in Belfast City Hall.
But with the Democratic Unionists fielding Mr Robin Newton and the Ulster Unionist Party due to nominate Mr Bob Stoker, many councillors were predicting a knife-edge vote.
Mr Morgan said: "I really think this is too close to call and I am quite realistic about what could happen.
"The Alliance Party's three votes will be crucial and also what the DUP group does, given their unhappiness over Bob Stoker's candidacy.
"I am humbled to have been chosen by the SDLP as its candidate. If elected my principal aim will be to ensure that divisions in Belfast are healed and not deepened.
"The SDLP will advocate a partnership approach between all parties and councillors at City Hall and I will seek to represent the ordinary decent citizens of this city.
"Regardless of who they are, what they are or where they are from, they are all important to the city."
The Democratic Unionists' Mr Newton said it was looking at this stage that Mr Morgan would become the SDLP's second Belfast Lord Mayor.
He accused the Ulster Unionists of trying to shut his party out of the top office for electoral reasons.
"It seems the ethos of power sharing which the UUP espouses does not extend to fellow unionists, to the DUP," he said.
Mr Jim Rodgers, deputy leader of the Ulster Unionist group on Belfast City Council, said: "We have selected former Lord Mayor Bob Stoker as our candidate because we believe he will best represent this city.
"The vote will be extremely close.
"There are a lot of things that could still affect the outcome - Alliance have one councillor, Naomi Long, returning from holiday, David Ervine of the Progressive Unionist Party has been returning from a visit to Sri Lanka, someone could be delayed on their way to the council or could miss the meeting because of a family reason.
"The vote is far from certain and given that council has still to complete its business from the May meeting, it could well be delayed."
PA