So, Donald Trump was being honest when he let it be known that he hadn't swotted up for the first presidential debate. He was horribly unprepared, and it showed. The great reality TV star put in a really bad live performance in front of 100 million-odd viewers.

Hillary Clinton was Hillary Clinton – smug, annoying, not half as clever as she thinks. A better debater would have demolished Trump – he gave her enough opportunities -- but she did not. Still, she was well-drilled and she sounded professional. Trump sounded incoherent, even by his low standards. He made a complete mess of almost every point. Or, as one Republican insider put it to me in a text message, 'He shit the bed, rolled around in the sheets, then licked them clean.'

The discussion started on the economy, and this was Trump’s strongest section. Even so, he didn’t exactly win. He laid into Clinton over ‘defective Nafta’, the free-trade agreement her husband made, and spoke with his usual garbled-but-effective rage about jobs being outsourced and globalisation. 'They're using our country as a piggy bank to rebuild China,’ he said, ‘and many other countries are doing the same thing.

Clinton, for her part, was hammy and over-rehearsed. She described Trump’s fiscal plan as ‘Trumped-up trickle-down’ economics, a joke which fell flat across the world. But then Trump – perhaps lacking something else to say – lost any advantage he might have had by embarking on a rambling aside about how the Fed has ‘gone political .. The Fed is being more political than Secretary Clinton.’ Lots of Americans thinks agree, but Trump didn't seem to know what he was saying.

Trump was sniffing a lot, which caused merriment on social media, and interrupting Hillary Clinton excessively. But then, hey, it’s Donald – lots of Americans seem to like his aggression. And, with his broad brushstrokes, Trump painted a more striking political picture than Clinton and her schoolmarmish elite economic progressivism.

But then the moderator Lester Holt asked Trump whether he would release his tax returns and what little composure he had shown seemed to slip. He kept saying his businesses were ‘underleveraged’ -- and that, ‘by the way’, his $650 million debt was not a lot of money. This hardly made him sound like a man of the people -- though Clinton missed the chance to make that point.

Trump insisted he would release his tax returns – ‘against my lawyers’ wishes’ -- but only if Clinton released ‘her 33,000 e-mails that have been deleted. As soon as she releases them, I will release.’

Clinton’s emails scandal should have been Trump’s ace card, but he didn’t play it very well. Clinton straight-batted with her usual ‘I made a mistake’ routine, and got away with it. Trump tried to say that she had forced her staff to ‘to plead the fifth’ rather than testify against her – but he could not conjure a gotcha moment. He seemed unable to goad Clinton into any major slips, and Clinton’s better preparedness was starting to tell.

As the debate went on, and became more boring, Clinton’s rhetorical superiority became ever more obvious. Trump prides himself on being a 'counter-puncher' but he didn't land any convincing blows. She needled him by denigrating his businesses, suggesting that Trump was not as rich as he made out, and saying he had ‘stiffed’ thousands of workers. Trump, agitated, returned fire by saying how bad the government was, and attacked the 'political hacks who support Hillary Clinton.' But he was often flailing. He would resort to restoring his pride by talking, as he always does, about his businesses and how beautiful they are. That always sounds silly. In the context of this formal presidential debate, it sounded hopeless.

The worst part of the evening for Trump was the section on the ‘birther’ issue – the hounding of President Barack Obama to show his birth certificate. Trump tried to suggest, again, that Hillary Clinton’s campaign of 2008 had started the conspiracy theory that Obama was not born in the USA. But he clearly had not mastered the information he was trying to disseminate. He did get a sharp line out about Hillary’s bogus sanctimony – ‘'When you try to act-holier-than-thou, it doesn’t work’ – but Clinton’s carefully constructed attack on his ‘birther’ record was damning.

Trump sounded reasonably tough, albeit vague, on law and order, although he was muddled on racial profiling. Clinton charged him with a history of racism, based on the fact that his family property business was sued by the Justice Department for discriminating against African-Americans. Trump dismissed that charge effectively, but then veered wildly off tangent, insisting he was not a racist because, well, 'In palm beach, Florida, tough community, a brilliant community, probably the wealthiest in the world. I opened a club, and really got great credit for it. No discrimination against African-Americans, against muslims, against anybody. And it's a tremendously successful club, and I'm so glad I did it, and I have been given great credit for what I did. And I'm very, very proud of it. And that's the way I feel. That is the true way I feel.'

Gee. Clinton, meanwhile, looked increasingly pleased with herself, and she grew in confidence as the evening went on. All her preparation was paying off. The teacher's pet was being rewarded. She had perhaps the most effective line of the night when she said, 'I think Donald just criticised me for preparing for this debate. And yes, I did. And you know what else I prepared for? I prepared to be president. And I think that's a good thing.'

On security, the last talking point, Clinton and Trump were both poor. There was an embarrassing exchange about ‘the cyber’ – in which the candidates sounded a lot like, well, a 68-year-old woman and 70-year-old man discussing the complexity of the internet. And then both candidates talked in platitudes about nuclear weapons.

Trump went after Hillary Clinton over the wars in Iraq and Libya – what should have been another winning argument for him, given her disastrous record as a stateswoman in those two countries. Again, however, he got stuck on the defensive. He spent far too long trying to insist he had not supported the war in Iraq. He sounded a lot like he was protesting too much, Hillary Clinton rather neatly countered that Trump had done business with Gaddafi. Trump ended the night whining pathetically about Clinton's attack ads: 'I will tell you this, Lester, it's not nice, and I don't deserve that.' So much for Mr Tough Guy.

Of course, this might not matter at all. Clinton is not about to suddenly become popular following tonight’s performance; she smirked and preened too much. Trump’s basic campaign narrative -- that he is the outsider taking on the Washington elite -- remains in tact. Trump fans will complain that the moderator treated their man unfairly – and it is true that Holt, a registered Republican, was more aggressive to the Republican candidate. There were no questions about immigration, the issue on which Trump has enjoyed most success. And perhaps debates don't change the dynamics of the race. But if anyone undecided tuned in tonight thinking Trump might be a brilliant one-vs-one debater, they would have been very disappointed.