Marco Rubio walked into the first Republican presidential debate on Thursday night as a decided underdog. But the youthful Florida senator emerged, surrounded on a stage of bombastic personalities, as a policy savant.

If Rubio can survive the Donald Trump war of attrition, observers agreed, he is primed for battle against Hillary Clinton.

It was a critical test for Rubio, who has in recent weeks taken a dip in the polls despite launching his run for the White House in April with soaring expectations. A slew of press reports even questioned if Rubio's "Obama- esque" appeal was sustainable, predicting an early demise for the candidate long regarded as a rising star within the Republican party.

But the senator seized on most of his allotted time in Cleveland (the seventh out of 10 candidates on stage) by articulating his prescriptions for economic, immigration and education policy, while presenting himself with an election aura that was capable of confronting the formidable Clinton operation.

Ohio governor John Kasich, well received on his home turf, was arguably the only other fluid candidate who made the most of a chance to elevate his national profile.

Cutting through the noise was no easy task with Trump, the property mogul and early frontrunner, taking his controversial presence from the stump to the stage. Trump pressed hard on contentious issues such as immigration reform while refusing from the outset of the debate to rule out a potentially destructive run as an independent candidate.

Avoiding Trump

While some opponents sparred unabashedly with the self-proclaimed billionaire – Kentucky senator Rand Paul, whose campaign has floundered, took on Trump early and often – Rubio's approach appeared to be one of near-avoidance.

When presented with a direct opportunity to respond to Trump on immigration, shortly after the former reality-TV star talked up the need to build “a big, beautiful door”, Rubio declined to address his opponent directly and stuck instead to his own proposals for the Mexican border.

“I also think we need a fence, but if El Chapo can build a tunnel under that fence, we need to deal with that,” Rubio said, referring to the escaped cartel kingpin Joaquin Guzman.

"Let me tell you who never get talked about in these debates," Rubio said. "The people who call my office, waiting 15 years to come to the United States. They've paid their fees, hired a lawyer and they're wondering if they should come in illegally."

The only time the first-term senator addressed Trump directly was to refute the mogul’s claim that he had donated to most of the Republicans sharing the stage.

"Not me, not me! Actually to be clear, he supported Charlie Crist, " Rubio joked, referring to the establishment- backed primary opponent he defeated in his long-shot bid for his Florida Senate seat.

"I think he was the winner of the second debate," said Liz Mair, a Republican operative who has advised four of the candidates, though not Rubio. "Throughout, he came off as very polished, policy-savvy, smart, positive and, perhaps above all, he looked the part – and I wasn't expecting that.

“There was a risk he could have come off as the little kid trying to play with bigger kids, and not keeping up. But he did a very good job.”

“If I’m our nominee, how is Hillary Clinton going to lecture me about living paycheque to paycheque? I was raised paycheque to paycheque,” said Rubio, invoking his biography as the son of a bartender and a maid. “How is she going to lecture me about student loans? I owed over $100,000 just four years ago.”

Abortion

Still, Democrats felt Rubio handed them a gift while discussing his views on abortion.When asked by the moderator over his support for rape and incest exceptions for abortion, as part of a string of questions on women’s rights that forced several candidates to play into an issue Democrats see as a stronghold, Rubio disputed her claim.

“I have never said that and I have never advocated that,” Rubio said, adding that “future generations will call us barbarians for murdering millions of babies when we never gave them a chance to live.”

The American electorate is broadly split between being pro-choice and anti-abortion, but exceptions for rape, incest or to save a mother’s life are supported by a strong majority.

Rubio has, in fact, supported legislation including such protections, and he has also backed measures without exceptions. He has also said in the past that he would sign a bill with exceptions as president if that’s the only option.

A spokesman for Rubio confirmed that the senator had signed on to legislation with exceptions, but said he had not actively advocated them.

Planned Parenthood

Jeb Bush, one of Rubio's key rivals and a former mentor, also staunchly defended his anti-abortion credentials days after landing in hot water for questioning the need to spend $500 million on women's health – a comment he later clarified was directed at Planned Parenthood.

Bush, the leading establishment Republican who has been second to Trump in most national polls, avoided any major stumbles but did not do much to distinguish himself from the rest of the field.

One of the former Florida governor’s standout moments arrived when he deftly defended his support for Common Core school standards, an education policy that is loathed by conservatives, instead of being put on the defensive.

But there, too, Rubio was ready with a response showing how most Republican primary voters perceive the issue.

The federal government “will turn it into a mandate”, he said. “In fact, what they will begin to say to local communities is, ‘You will not get federal money unless we do things the way they want you to do it’. And they will use common core or any other requirement. . . to force it down the throats of our people and our states.”

Guardian service