Trump lashes out at debate moderator

He rambled and struggled to make concise points. Asked about his tax returns, Mr Trump embarked on an explanation of why he wouldn't release them. But then he meandered, unbidden, into speculation about the value of one of his buildings, and finished by declaring America a "third world country". All this in the same breath.

And in his frustration, Mr Trump seemed to forget to try to steer the conversation towards his own talking points. The 90 minute debate, for example, was almost devoid of any discussion of immigration. Building a wall along the southern border of the United States is one of Mr Trump's main policies, but there was barely any mention of it.

The rhythm of the evening was instead controlled by Mrs Clinton. Poised and prepared, it was as if she had lived almost every moment of this debate before. For weeks and months she and her team had poured over briefing papers, discussed attack lines, and rehearsed answers.

She had talking points for every topic, and was ready for Mr Trump's responses.

"For 40 years everyone running for president has released their tax returns," Mrs Clinton said when asking why Mr Trump had not released his. "Maybe he doesn't want the American people to know he has paid nothing in federal income taxes."

Mr Trump quipped: "That makes me smart."

But she immediately hit back: "That means zero for troops, zero for veterans, zero for health."