Mentioning the Blair word
Nicola Sturgeon plainly felt she had delivered the ultimate insult - not least because she kept it until the very last word of her exchanges with Labour's Johann Lamont.
Building to a crescendo, she constructed the condemnation. Johann Lamont was "warming" to Conservative policies. She was a "poster girl for the Tories."
And, then, the culmination. Her eyes burning, Ms Sturgeon glared at her rival and declared: "Johann Lamont, new Blair."
The chamber gasped. How could she? Would the Presiding Officer intervene to chide her for her foul language?
She had referred to Blair! She had compared the Scottish Labour leader to Tony Blair! You remember? The hate figure - who won all those landslide victories.
The topic, of course, was Ms Lamont's speech in which she had questioned the relative value of free stuff in Scotland - such as higher education and prescriptions - while also challenging the cash devoted to the likes of a council tax freeze and police numbers.
Nicola Sturgeon gleefully echoed one of Ms Lamont's predecessors in welcoming the prospect of a debate on these terms. "Bring it on", she hollered.
Mind you, Ms Lamont did have one vocal supporter during the exchanges. Ruth Davidson, who heads the Tories, seemed happy that she was no longer alone in what she called "the Dutch auction" to tempt the voters with goodies.
The Tories, Ms Davidson recalled, had previously been a solitary voice at the Holyrood elections challenging the wisdom of policies such as free prescriptions. No doubt it was lack of time which prevented Ms Davidson from recollecting what had happened to the Tory vote at those elections.
Still, these were excellent, robust exchanges between Ms Lamont and Ms Sturgeon - who was deputising for Alex Salmond. The FM is watching golf in America. (Behave yourself - it's got nothing to do with his handicap. It's the Ryder Cup - we host it next. Plus he's chasing US investment.)
Ms Lamont suggested that the SNP were ducking the issue of overall spending cuts because they did not want to frighten the voters in the run up to the referendum. They were not, she suggested, being honest: ignoring even the questioning of universal provision in the Beveridge and Christie reports to government.
Little was gained, she suggested, from free prescriptions if the NHS was shedding nurses. Little was gained from a council tax freeze if schools were short of resources.
In response, Ms Sturgeon laid the charge of dishonesty at Labour's door. They had gone into the council elections, she said, promising a continuing council tax freeze.
Further, she said that the SNP had won an outstanding election victory promising the very policies now questioned by Ms Lamont. The people, she said, had chosen - and they had not chosen Labour.
The SNP, she argued further, had delivered those policies within a balanced budget designed to stimulate economic growth within the limited resources available.
Willie Rennie, meanwhile, took a different tack entirely, urging Ms Sturgeon to improve the provision of nursery care to two year olds.
Ms Sturgeon switched from combative to consensual.
She even noted in a warm tone that it was Mr Rennie's birthday: an anniversary he apparently shares with the Deputy FM's father. The day, that is, not the year.