The three-time former premier was sentenced last year to seven years in jail and banned from holding public office for having sex with "Ruby the Heart Stealer" at what prosecutors described as erotic parties at his luxury home.
The punishment was suspended during the appeals process, but the tycoon's other legal woes were catching up with him, and in May he began serving up to a year of community service for tax fraud in a widely publicised fall from grace.
"The Ruby affair seemed like the decisive case that would mark his downfall, but it has become just one of many episodes in his political decline, his agonised fall from power," historian and Berlusconi author Antonio Gibelli said.
The media magnate, who has largely dropped out of public view since starting his community service, is unlikely to be in court Friday for the first hearing in the Ruby appeal trial, which is expected to deal with administrative issues.
Berlusconi, 77, has repeatedly denied having sex in 2010 with then 17-year-old exotic dancer Ruby – whose real name is Karima El-Mahroug – during parties that witnesses said featured nudity and strippers dressed as nuns.
He was also found guilty of abusing his powers by calling a police station to press for the busty glamour girl's release from custody when she was arrested for suspected theft.
His defence claimed he believed El-Mahroug was the niece of former Egyptian president Hosni Mubarak and wanted to avoid a diplomatic incident, but prosecutors insisted that was a bid to conceal their relationship.
Sordid allegations of depraved sex acts and the conviction of three of Berlusconi's allies for procuring prostitutes for him kept the story on Italy's front pages for months, but interest has waned with the politico's downfall.
Should the appeals court uphold the guilty verdict, the case is likely to go to the Supreme Court. If definitively convicted, Berlusconi will serve his sentence under house arrest thanks to lenience towards convicts aged over 70.
As the billionaire flounders under mounting legal woes – he is also on trial for allegedly bribing a senator and under investigation for tampering with witnesses – his centre-right Forza Italia party is suffering.
His expulsion from the Senate in November following his tax fraud conviction marked an irreversible decline in both his and Forza Italia's fortunes.
'Air of defeat'
Once a formidable political force, the weakened and divided party was dealt an embarrassing blow at the European elections in May, coming in a poor third behind the centre-left Democratic Party and the anti-establishment Five Star Movement.
"Berlusconi's mistake was believing his power was eternal. Forza Italia has to stop thinking he is irreplaceable, and find new leadership," said Gianfranco Pasquino, political science expert at the Johns Hopkins School in Bologna.
The ageing former premier, who burst onto the scene in 1994, shaking up the postwar status quo and winning over millions of Italians with the help of his vast television empire, has suffered from the stellar rise of the fast-talking, charismatic Matteo Renzi, 39, who shot from Florence mayor to prime minister earlier this year.
"His problems have also been compounded by the legal turmoil surrounding two of his closest collaborators, Marcello Dell'Utri and Claudio Scajola," Gibelli said.
Business ally Dell'Utri was extradited from Lebanon this month to serve time behind bars for dealings with the mafia, while Scajola, who was industry minister under Berlusconi, was arrested in May on suspicion of helping a former Forza Italia lawmaker convicted of mafia association flee justice.
"There is an air of defeat in Berlusconi circles. The man himself has become a decidedly pathetic figure, sidelined by his own party, refusing to accept that his era is over," Gibelli said
According to Pasquino, while a guilty verdict in the Ruby case would hurt Berlusconi personally, at this point "it will have no effect on Italy's political scene."
"Berlusconi's career in politics is over, and he has no chance of making a comeback," he said.