Vice President Joe Biden's assertive debate effort righted the Democratic ship but the pressure is still on Barack Obama to come back from his own dismal performance if he wants a second term.
Obama's re-election hopes have hung in the balance since Mitt Romney knocked him about for 90 minutes on 3 October in the first presidential debate, with the incumbent seeming passive and putting up little resistance.
Biden stepped up to the plate on Thursday night needing a more robust performance if he was to slow the momentum of the Republican ticket, with Romney having seized the lead in several national opinion polls.
"The most obvious takeaway was how much more combative it was," Charles Franklin, politics professor and co-founder of Pollster.com, told AFP. "If the Democrats wanted Biden to be more aggressive, they certainly got that.
"It's hard to say if it has changed the momentum of the race in a dramatic way, but I think it was a vigorous enough performance and it certainly did not reinforce the passivity that we saw from Obama last time."
Biden set about Romney's running mate Paul Ryan with relish, appearing incredulous at many of his statements and punctuating his replies with astonished exclamations like "Amazing!" "Incredible!" and "Malarkey!"
He brought up Romney's "47 percent" remarks, when the Republican nominee appeared to write off almost half the electorate, but Ryan dodged the bullet well, reminding the electorate that Biden is prone to gaffes himself.
Unlike last week's presidential debate, much of Thursday's encounter centred on foreign policy and Biden called out Romney and Ryan for having no other answers despite their criticisms on Iran, Syria and Afghanistan.
"Are you going to go to war? Is that what you want to do now?" the vice president challenged his opponent, 27 years his junior, on Iran.
Dotty Lynch from the American University told AFP that the Democrats she had spoken to were happy with Biden's performance.
"They are energized by it, they say he didn't let Ryan get away with anything, he stepped in when he heard something he wanted to refute."
But Ryan, a rising Republican star who is chairperson of the House budget committee, didn't discredit himself either as he showed a good grasp of policy and hit back hard at his more experienced opponent.
"Paul Ryan was knowledgeable, got his points across, and I think maybe surprised people about his command of facts on international issues, an area that he hasn't done very much in," Lynch said.
"My sense in the broader picture is that partisans of both sides could find a good deal to like about what their candidates did," Franklin said.
"I did not think Ryan made any disqualifying kinds of mistakes. He didn't betray a fundamental lack of knowledge."
But it was Biden who clearly had the ground to make up as Democrat-leaning Washington Post columnist Carter Eskew pointed out.
"I doubt this Biden victory will make a lasting difference in the race's trajectory. But a Biden 'loss' certainly would have," Eskew wrote.
With just three-and-a-half weeks to go, Romney and Obama are neck-and-neck in national polls, but the president has slim leads in the majority of the so-called swing states that will decide the 6 November election.
"Obama still has the edge at the moment if you just look at what we do have out of the swing states, but Romney has closed that edge in several of them," said Franklin, acknowledging a tightening race.
Whether the president can prevent those battleground states from tilting toward Romney will likely depend on how he fares in their next clash in five days, the polling expert said.
"That is the million dollar question. What does Obama do in the second act? Does he show he can rise to the challenge?
"And on the Romney side, can he pull it off twice in a row? The next two presidential debates are terribly important," Franklin said.