She's just one point ahead of Sinn Féin leader Gerry Adams, even though he's dropped 7 points since August.
Taoiseach Enda Kenny's rating is also down by six points to 29 per cent, his lowest since becoming Taoiseach.
A separate poll in the Sunday Business Post shows support for Fine Gael down 2 to 26, with Labour unchanged on 8 per cent.
Fianna Fáil remain stable on 18 per cent, while Independents and others have climbed by five points.
Political Editor with the Sunday Times, Stephen O'Brien, says the coalition parties are clearly feeling the effects of public anger over the introduction of water charges.
