* Former premier faces off with critics to win back support
* Media-savvy mogul revives theatrics to win spotlight
* Berlusconi party dominates airwaves before Feb. 24-25 vote
By Catherine Hornby
ROME, Jan 21 (Reuters) - Silvio Berlusconi has always been most formidable with his back to the wall and he has played a bold gamble by leaving the comfortable studios of his own television empire to take on some of his fiercest critics ahead of next month's Italian election.
In previous campaigns, the 76-year-old media billionaire, who owns Italy's biggest private broadcaster, could rely on respectful questions and no interruptions but after the scandal and financial crisis that drove him from office in 2011, this time, journalists have smelled blood.
To the discomfort of his opponents, he appears to be revelling in the challenge and is slowly cutting back the opinion poll lead held by the centre-left Democratic Party (PD)after a blitz of just about every television talk show in Italy.
"Berlusconi has found the courage to confront the kind of challenges that he didn't usually face in previous election campaigns when he had the advantage," political communication expert Marco Marturano said.
"This strategy of facing enemies in the press is paying off, and opinion polls are reflecting that."
Berlusconi is head of the centre-right alliance but has said its candidate for prime minister will be decided after the elections and it will not be him. Nevertheless he has been spearheading its campaign in the weeks ahead of the vote.
A poll released by the SWG research institute on Friday showed support for the centre right rising about 2 percentage points to 27 percent in the past week, which follows Berlusconi's appearance on one of his critics' talk shows.
The tycoon, facing several trials on charges including tax fraud and paying for sex with a juvenile prostitute, has narrowed the gap with Pier Luigi Bersani's centre-left coalition by 4 percentage points versus the week before, but still trails by 6 percentage points.
Berlusconi, who resigned as prime minister in November 2011 when Italy came close to a Greek-style meltdown, amassed a fortune from the launch of his Mediaset TV empire in the 1970s, and owns Italy's three largest private networks.
But nearly 9 million viewers switched to La7, a private channel he does not own, on Jan. 10 to watch Berlusconi confront Michele Santoro, a journalist who has made a career out of attacking him.
After explaining his campaign points clearly and deflecting questions about his alleged "bunga bunga" sex parties, the three-hour interview was overwhelmingly viewed as a success for Berlusconi in the media debate it prompted.
A natural showman, Berlusconi has always seen television as a comfortable medium and it is the key channel for reaching his traditional electorate among middle-aged and elderly generations.
Since the end of December, he has appeared daily on television and radio talk shows, carpeting the airwaves with his usual promises to cut taxes and prompting watchdog Agcom to complain of his excessive presence on some programmes.
Research published by La Stampa daily on Friday showed Berlusconi had appeared on TV for 63 hours from Dec. 24 through Jan. 13, more than double his left-wing rival Bersani on 28 hours and also beating outgoing Prime Minister Mario Monti's 58 hour-presence as a campaigner.
Data from media watchdog Agcom showed Berlusconi's People of Freedom party hogging the most air time on state broadcaster RAI's three main news programmes and on his own Mediaset news bulletins from Jan. 7 to Jan. 13.
The numbers alone, however, do not tell the whole story and neither Bersani, who can appear dull and plodding, nor Monti, who often sounds like the economics professor he is, have been able to match Berlusconi's feisty performances.
Marturano said that some presenters who used to go easy on Berlusconi have turned against him, fearing he is a sinking ship but previously hostile journalists have shown him more respect for agreeing to appear on their shows.
It is a long way from the kid-glove treatment typified by an occasion in 2001 when Bruno Vespa, a veteran of RAI state television, stood by in respectful silence while Berlusconi signed a "contract" with Italian voters on the network's main talkshow.
This year, even Vespa has taken a tougher line, interrupting Berlusconi during a recent interview to imitate one of his famously long-winded monologues.
But few have managed to knock him off his stride or halt the flow of theatrics that spice up his tirades against targets ranging from Monti to German Chancellor Angela Merkel or the magistrates who have forced him repeatedly to stand trial.
Comical stunts aimed at stealing the spotlight still come easily to Berlusconi and he performs them at every opportunity, jokingly hitting one journalist over the head with a cardboard sign or pulling out a handkerchief to clean a chair where one of his critics had been sitting.
Whether the campaign will be enough remains to be seen but with just over a month to go to the election on Feb. 24-25, the effect is starting to be felt.
"Politics is communication too. Energy, getting through to voters," Luca Ricolfi, one of Italy's leading commentators wrote in the daily La Stampa in an editorial entitled "And if Berlusconi won again?" (Editing by Alison Williams)