Leaders' debates are far less important in Australia than in US presidential elections. That's because we don't need to fall in love with our leaders - just respect them and ask them to get the job done.
But when you demonise an opponent, as Labor has done with four years of relentless personal attacks on Abbott, a single good debate performance can bring your strategy undone.
This is what happened in one of the great US presidential debates of modern times. In 1980, president Jimmy Carter, a nerd in anyone's terms, was up against Ronald Reagan, the California governor derided as a B-grade actor and a secret extremist.
But Reagan was calm, measured, engaging and presidential - much like Abbott last night. Rudd is a complex character. There are layers and layers, countless contradictions. Abbott is more straightforward. He is easier in his own skin.
This came across strongly last night. People tend to forget that Abbott has more frontbench experience than Rudd and Julia Gillard combined. Abbott may tend to speak in slogans for the nightly news, but last night he was fluent and straightforward. Rudd's sometimes flowery locutions can be a bit weird.
Notably there was no foreign policy beyond boats. However, some of Rudd's statements in this area were bizarre.
It is astonishing that Rudd should blame the Sri Lankan civil war for a flow of boatpeople. The Sri Lankan civil war ran for decades. It didn't start under Rudd. It ended on Rudd's watch, so it didn't cause the boats.
Similarly, Rudd was just flat out dead wrong to say that 70 per cent of people who went to Nauru under the Pacific Solution came to Australia. As Abbott pointed out, it was 40 per cent. How could Rudd get this so wrong? It was a killer moment.
This is why Abbott was also on strong ground in saying the PNG Solution is not what Rudd says it is. At least this time Rudd had the sense not to repeat his absurd and irresponsible claim that turning boats around would lead to armed conflict with Indonesia.
One totally baffling statement from Rudd concerned kids at school supporting their parents.
On substance, Abbott clearly did better. The policy wonk was not convincingly wonkish. The nerd was unreliable on the facts.
Abbott looked completely prime ministerial. Debates count most when they run totally counter to one side's narrative.