Between 10 per cent and 20 per cent of Scotland's population are undecided voters who will dictate the outcome of this referendum come 18 September – and they were the targets for both campaign teams as proceedings got under way in Glasgow.
Expectations were that Salmond, a formidable debater, would run rings around Darling, a safe pair of hands.
In the preamble, commentators had urged Darling to "bore for Britain" and play a "straight bat" to Salmond's fanciful and romantic proposition. For some nationalists, the debate represented a potential game changer to shift polls in favour of independence.
Both men looked nervous at the outset but quickly hit their stride after the opening salvos. Contrary to expectations, Darling was fired up.
There was lots of finger-pointing and a clear plan to not let Salmond dictate the exchanges (which he normally does at Holyrood). The First Minister was perhaps a bit too casual during his cross-examination of Darling as he led with (what now look ill-judged) scare stories about aliens and driving on the other side of the road rather than focusing on the weaknesses of the Unionist case.
The format worked well as moderator Bernard Ponsonby invited audience participation. The exchange between the two principals was robust and entertaining and both men were happy to land the low blows when required.
Better Together will be happy as Darling went hard on the issue of a shared currency and Salmond's lack of a Plan B. The Yes Scotland campaign will be pleased that Salmond exposed Better Together as not having a coherent proposal for more powers.
The outcome? An exit poll for The Guardian gave the victory to Darling by 56 to 44 and it would be hard not to argue that the Better Together camp had a better night than the nationalists. Despite this, Yes Scotland will be encouraged by polling before and after the debate that indicated there was a further shift to its campaign from undecided voters.
Did we learn anything new? Probably not. Neither side managed to gain clear water. The same well-rehearsed arguments were rolled out for undecided voters and those just getting engaged in the debate.
Expect more of the same to come.
Conor Magowan is a director and head of public affairs at Weber Shandwick Scotland