Casting himself as the big-city mayor who turned a declining, crime-infested metropolis into a hub of wealth and opportunity, Rudy Giuliani will air his first television ad of the campaign this week in early-voting New Hampshire, a state where the national GOP frontrunner is still trailing.

The 60-second ad, called "Tested," highlights Giuliani's work as mayor revitalizing New York City in the years before the Sept. 11 attacks, a history the candidate has worked to highlight for months.

"They used to call it unmanageable, ungovernable," Giuliani says in the ad, calling New York "a city that was in very, very difficult condition when I became the mayor."

As he speaks, images of police handling a crime suspect, of tenements and of X-rated shops appear on the screen. The images then change to upbeat, sunny shots of joggers and couples and families moving into their city homes.

"By the time I left office, New York City was being proclaimed as the best example of conservative government in the country," he says, taking credit for sweeping the streets of crime and lifting the city's residents out of poverty.

The ad represents a new phase for Giuliani, as he tries to strengthen his fragile poll numbers in New Hampshire. The campaign sought to avoid the airwaves as long as possible to see how far name recognition would take him, and to save up money for the battle against multi-millionaire Mitt Romney. Romney has consistently led the polls in New Hampshire — a recent CBS poll showed him with 34 percent while Giuliani was tied with Arizona Sen. John McCain with 16 percent.

The Giuliani strategy is centered around doing well in the early states, but is especially focused on the nearly 20 Republican primaries set for Feb. 5. The campaign has already spent a couple million dollars in New Hampshire on radio ads and direct mailings touting his mayoral record.

At the end of his New Hampshire television ad, Giuliani reinforces the message that he is not a perfect candidate, but has the best experience in the field.

"I've been tested in a way in which the American people can look to me. They're not going to find perfection, but they're going to find somebody who has dealt with crisis almost on a regular basis and has had results, and in many cases exceptional results. Results people thought weren't possible," Giuliani says.

The "Tested" ad is scheduled to air from Nov. 15-20 on stations in Manchester, N.H., and Boston at a cost of more than $300,000, according to TV advertising data from another presidential campaign.

Romney, lesser known nationally, has been on the television airwaves since the beginning of the year, particularly in Iowa, the state that holds the first presidential caucuses. Other Republicans contenders, such as John McCain, Fred Thompson and Ron Paul, have also filled broadcast time in early contest states.

Giuliani was mayor during a steep decline in crime, a decline that began gradually three years before Giuliani took office. According to FBI statistics, crime decreased by 60 percent between 1993, the year before he became mayor, and 2002, when he left. Crime was also declining nationwide, but not quite as dramatically, decreasing by 24 percent during the same period.

FOX News' Mosheh Oinounou and The Associated Press contributed to this report.