The First Minister has claimed Better Together leader Alistair Darling will "have the heeby jeebies" if he takes him on in a television debate over Scotland's future.
Alex Salmond spoke out after a clash between the rival campaigns over the timing of a TV showdown between the First Minister and the former chancellor.Mr Salmond has accepted an invitation from STV to take on Mr Darling on August 5, his spokesman said.
But the Better Together campaign said it was ''disappointed'' that the STV debate would not take place on July 16, as the broadcaster had originally planned.
Meanwhile, the pro-UK campaign has accepted an invitation from the BBC for Mr Darling to take part in a TV debate on on August 12, but the First Minister has not yet agreed and is giving it ''due consideration''.
Mr Salmond has repeatedly insisted he should debate Scotland's future with David Cameron, although the Prime Minister has consistently refused to take part in such an event.
The First Minister told 5 News: "I think that a debate is a good idea and I want to debate with the Prime Minister, of course, as we should do because our names are on the Edinburgh Agreement - the Prime Minister and the First Minister. It is a debate which overwhelmingly the people of Scotland want to see.
"But I have given him a deadline of the Commonwealth Games and if he doesn't debate by the start of the Commonwealth Games then I will debate with his substitute - Alistair Darling or whoever.
"Whether that will happen, my view is that Alistair will have the heeby jeebies now.
"It is all very well saying you will do something in theory but when it comes down to the practice - well, we will see what happens."
A Better Together spokesman said: "Alex Salmond seems to go out of his way to embarrass himself.
"What a ridiculous comment for the First Minister of our country to make. Alistair has already accepted the original invitations to debate from both STV and BBC."