Republican vice-presidential candidate Mike Pence held a slight edge over his Democratic rival Tim Kaine in their head-to-head meeting, experts say, in what was deemed a pretty even fight.
"Tim Kaine entered the night with too much adrenaline and constantly interrupted Mike Pence throughout the course of the evening," said Mr Aaron Kall, director of debate at the University of Michigan. "This was a similar tactic employed by Trump in New York and it failed both candidates with the viewing audience and undecided voters."
A CNN/ORC poll of debate watchers showed Mr Kaine's unfavourability rating go up from 28 per cent to 40 per cent. Mr Pence's held stable at about 40 per cent before and after the debate on Tuesday night.
Credit was given to Mr Pence for his calm demeanour throughout, even as Mr Kaine pushed him to defend comments made by Mr Donald Trump, who had called Mexican immigrants rapists and criminals, and women slobs, pigs and dogs.
"Pence faced the impossible task of defending all Trump's statements during the campaign. He did the most admirable job possible, but the fact-checking organisations in the coming days will likely be unkind to many of his assertions," Mr Kall said.
Were minds changed by the debate? Probably not. They defended themselves and their presidential candidates in articulate but predictable ways.
ROBERT SCHMUHL, professor of American studies at the University of Notre Dame.
Key moments from the debate
Pence: What I can't understand is Hillary Clinton - how she can support a process like partial birth abortion... At the very idea that a child almost born into the world could still have its life taken from it; I cannot in conscience (understand) a party that supports that.
Kaine: We support the constitutional right of American women to consult their own conscience and make their own decision about pregnancy. That is something we trust American women to do... The last thing governments should do is to have laws that would punish women who make reproductive choices.
Who won: They each spoke to their own support base. Mr Kaine squared his religious views with upholding the Constitution and giving women the right to choose, hoping to appeal to women voters. Mr Pence appealed to conservatives who are pro-life.
ON NUCLEAR PROLIFERATION
Kaine: Donald Trump believes the world will be safer if more nations have nuclear weapons... When he was... told, wait a minute, terrorists could get those, proliferation could lead to nuclear war, here's what Donald Trump said, and I quote: "Go ahead folks, enjoy yourselves." I would like Governor Pence to tell me what is so enjoyable or comical about nuclear war.
Pence: After (Hillary Clinton) travelling millions of miles as our secretary of state, after being the architect of the foreign policy of this administration, America is less safe today than it was the day Barack Obama became president.
Who won: At first, Mr Pence tried to avoid addressing Mr Trump's cavalier attitudes towards nuclear proliferation. Later, he brushed off Mr Trump's comments by saying: "He never said that." Mr Pence simply could not defend his running mate on this count.
ON CONFLICTS OF INTEREST
Pence: While (Clinton) was secretary of state, the foundation accepted tens of millions of dollars from foreign governments and foreign donors... And then we found... more than half of her private meetings when she was secretary of state were given to major donors of the Clinton Foundation.
Kaine: The State Department did an investigation and concluded that everything Hillary Clinton did as secretary of state was in the interest of the United States.... Now, let's compare that with the Trump Organisation. The conflict of interest could only be known if Donald Trump would release his tax returns and he has refused to do it. His son has said the organisation has a lot of business dealings in Russia.
Who won: Both vice-presidential candidates were evenly matched. Mr Pence managed to raise doubts about whether Mrs Clinton acted in her family foundation's interest while she was secretary of state, while Mr Kaine raised questions about Mr Trump and whether he would conduct foreign relations with his company's interests in mind.
For example, when Mr Pence was pushed to defend Mr Trump's statement that the world would be safer if more countries had nuclear weapons, he simply brushed it off by denying that Mr Trump had said that - when, in fact, he did.
But "Pence was able to discuss issues like Clinton's private e-mail server and foundation, which were relegated to the back-burner at Hofstra University," said Mr Kall. Mr Trump had noticeably failed to push Mrs Hillary Clinton on these issues during last week's presidential debate in New York.
Mr Kaine too had his moments, finishing strongly when he directly addressed a question about balancing personal faith and a public policy position.
Talking about his opposition to the death penalty while being the governor of Virginia, he said: "It was very difficult to allow executions to go forward, but in circumstances where I didn't feel like there was a case for clemency, I told Virginia voters I would uphold the law and I did."
Associate professor of political science Matthew Wilson at Southern Methodist University in Dallas, an expert in politics and religion, said: "It surprised me that he chose that issue, but it's a smart choice - it shows him actually ignoring his faith to take conservative action."
Overall, experts were not certain if the debate would affect either presidential ticket in a major way.
"Were minds changed by the debate? Probably not. They defended themselves and their presidential candidates in articulate but predictable ways," said American studies professor Robert Schmuhl of the University of Notre Dame.
Mr Kall noted any win on Tuesday night at Longwood University in Virginia would be only temporary.
"Pence will likely be perceived as a slight winner tonight, but everyone's attention will immediately shift back to the top of the ticket on Sunday night."