MANCHESTER, N.H. — His pledge to stay positive in ashes, Newt Gingrich challenged front-runner Mitt Romney to account for his record as a corporate takeover artist Monday as Republican presidential hopefuls hustled through a final day of campaigning for the New Hampshire primary, a pivotal test for the rivals bidding to derail the former Massachusetts governor.

The candidates were all but tripping over each other, concentrating their day in the southern half of the state, known for holding town-hall meetings in actual town halls.

One exception, Texas Gov. Rick Perry, campaigned in South Carolina but joined Gingrich from afar in going bluntly after the front-runner’s private-sector credentials.

“I have no doubt that Mitt Romney was worried about pink slips — whether he’d have enough of them to hand out,” Perry told several dozen breakfast patrons in Anderson, S.C. That was a slap at Romney’s recent comment that he worried about getting a pink slip during his executive career.

Perry cited South Carolina companies that downsized under the control of Bain Capital, the private equity firm Romney ran, and said it would be an “insult” for Romney to come to the state and ask for voters’ support in easing economic pain.

“He caused it,” Perry said, describing himself as best positioned to untangle the “unholy alliance between Washington and Wall Street.”

Among the half dozen contenders, Jon Huntsman, who needs a strong New Hampshire performance to stay viable in the race, planned perhaps the most frantic pace, with seven stops on his itinerary from Lebanon near the Vermont line to the seacoast.

The former Utah governor visited a Lebanon truck stop and took the phone from an employee behind the counter who was speaking with a milk delivery driver. He said he’s looking for votes wherever he can find them. “I’m the underdog,” he said, a label that applies — at least in New Hampshire — to anyone but Romney.

Knocking Romney off his perch Tuesday won’t be easy.

He has spent the better part of two years essentially adopting the state as his own and now holds a comfortable lead in pre-primary polls as his rivals essentially battle for second place. Romney won the Iowa caucuses last week by a scant eight votes over Rick Santorum.

In Nashua, Romney kept above the Republican fray at one stop Monday and went after the Obama administration for the soured taxpayer investment in Solyndra, a solar energy company that went bankrupt and laid off its 1,100 workers after getting a $528 million Energy Department loan.

He said government should support the conditions for letting the private sector work freely, not interfere on behalf of specific companies. “Let markets work,” he preached.

Romney has bragged about creating more than 100,000 jobs at companies he helped start up or turn around while at Bain but has not substantiated the claim. Gingrich said on NBC’s “Today” show that voters deserve more than that.

Gingrich, still smarting from a damaging barrage of negative ads in Iowa by Romney allies, vowed to draw a “very sharp contrast” with Romney, political shorthand for counterattacking. That effort was evident in weekend debates, when the former House speaker upbraided Romney for “pious baloney,” and it will become more so thanks to a new film, sponsored by a political committee supportive of Gingrich, that accuses Romney of “reaping massive awards” at Bain Capital at the expense of companies taken over by the firm.

Gingrich hastened to say he hadn’t seen the film, just as Romney tried to maintain an arm’s length from the anti-Gingrich political committee ads in Iowa. But Gingrich said pointedly that he understands the film looks at “where they apparently looted the companies.”

“He owes us a report on his stewardship” in the private sector, Gingrich said.

As for his own prospects, Gingrich said on CBS’ “This Morning” that he expected to do “well enough” in New Hampshire on Tuesday to campaign effectively in South Carolina, the first Southern primary. “It will be very clear the game is on between a Reagan conservative and a Massachusetts moderate,” he predicted.

Roughly $5 million has been spent on TV ads in New Hampshire by candidates and political action committees aligned with them — called super PACS — with most of the money coming from a pro-Huntsman group and Texas Rep. Ron Paul. Romney has spent roughly $1 million.

Huntsman skipped Iowa in hopes of a breakout showing in New Hampshire. Similarly, Perry is bypassing New Hampshire and aiming to revive his candidacy in South Carolina, which votes Jan. 21.