Pro-independence campaigners expect a boost in support after Alex Salmond's performance in a key television referendum debate.
The First Minister and Better Together leader Alistair Darling clashed in the BBC debate in Glasgow last night with currency, oil revenues, the NHS and the future of nuclear weapons the main subjects of a heated discussion.
Research by ICM for the Guardian newspaper showed 71% of people questioned thought Mr Salmond had been the better performer in the programme, compared with 29% for Mr Darling.
Yes Scotland chief executive Blair Jenkins welcomed the results of the ICM poll and expects undecided voters will move towards the pro-independence campaign.
Speaking on BBC Radio Scotland, he said: "We heard wall-to-wall sunshine in the weather forecast and I think it's wall-to-wall sunshine for the Yes campaign as well. People will be enormously strengthened and I think will take a lot from last night.
"More important than anything else, I think voters who are still making up their minds will have no doubt where the best arguments are."
He added: "This is not a presidential election, this is not about voting for a politician or a party. It's much, much bigger and much more important than that, so I think you won't necessarily get people moving instantly from last night but they will now reflect on what they saw and heard."
Speaking for the Better Together campaign, Labour MP Douglas Alexander told the same programme: "I think there's a difference between performing and persuading. If these debates determined the outcome of elections in terms of performance, I expect Nick Clegg would be Prime Minister this morning.
"I think he (Alistair Darling) asked the questions we need answers to. Postal ballots drop in 48 hours' time, we're still in a position where we don't have clarity from the First Minister in relation to currency, pensions and oil and actually, I think, the Yes campaign are where they did not expect to be, they're haunted be a series of basic questions as the postal votes drop."