It has been a recurring story throughout the English Boas has not been under as much pressure as he is now.

The club's FA Cup aspirations took a hit this past weekend when the Blues were held to a 1-1 home draw by Championship side Birmingham City, forcing a replay at St. Andrew's.

Chelsea has already been eliminated from the Carling Cup after a home loss to Liverpool in November, and with the West London club sitting 17 points adrift of league-leader Manchester City, the Premiership title is all but out of reach.

But speaking ahead of Tuesday's Champions League clash against Napoli, Villas- Boas presented his case as to why he should still have the backing of Chelsea's management, despite what appears to be a season without silverware at Stamford Bridge.

"You have to understand that this club, from 2004 up to now, has made a dramatic change for the best in terms of their past," Villas-Boas said. "It's the richest part of Chelsea's history, full of trophies and success, and you want to perpetuate that into the future.

"To do that, you have to sometimes make changes because you cannot sustain the same habits that you had in 2004, when this environment and team was created to make a winning team."

The most glaring change that Villas-Boas hopes to see is a shift away from the club's penchant for a "revolving door" on the managerial front in an effort to find a constant figure to look over the first team for the long haul.

Since the departure of the supremely successful Jose Mourinho in September of 2007, four men deputized on the Stamford Bridge sidelines until Villas-Boas was hired last summer, and Chelsea has averaged a trophy per season since Mourinho's exit.

But with Chelsea still taking home its fair share of silverware over the past few seasons, what justification is there for the club to keep Villas-Boas on board when previous managers have found success only to be sacked?

Avram Grant picked up the pieces after Mourinho left and guided the Blues to the Champions League final, something Mourinho failed to achieve with Chelsea. But just three days after the loss to Manchester United, Grant's contract was terminated.

Luiz Felipe Scolari was brought in during the summer of 2008 after successful stints with the Brazilian and Portuguese national teams, but he did not even last a full year as he was fired due to a poor run of form at a crucial point in the season. Scolari was replaced by caretaker manager Guus Hiddink, who led the Blues to FA Cup glory the same season.

Carlo Ancelotti's appointment the following summer was viewed as a big hit, bringing proven pedigree to Stamford Bridge after winning loads of titles with AC Milan. The Italian's first season at Chelsea was a success - he helped the Blues claim the Community Shield, FA Cup and Premiership title - but a sophomore season without silverware led to Ancelotti being sacked less than two hours after the club's final game of the season.

Enter Villas-Boas, who was, coincidentally enough, Mourinho's protege. Villas- Boas worked under the Real Madrid manager at Chelsea and Inter Milan. Villas- Boas was hired to succeed Ancelotti after the Portuguese tactician enjoyed an undefeated campaign in the Primeira Liga and a Europa League title with FC Porto.

Despite the success Villas-Boas brought to Porto in his one season at the Estadio Dragao, he has not been able to apply the same winning formula at Stamford Bridge, leading pundits to speculate whether he is the right man for the job.

In fairness to Villas-Boas, he basically inherited Ancelotti's squad and only added a couple pieces of his own, raising questions whether the results would be different if the Portuguese prodigy was able to start from scratch and assemble his own preferred squad.

But past Chelsea managers have been able to find success in their debut seasons after inheriting the preceding regime's squad, so why should Villas- Boas be held to a different standard?

It may just be too soon for Villas-Boas to manage a club of Chelsea's stature. At 34 years old, Villas-Boas is only in his third season of management at the club level.

Perhaps Villas-Boas has been given a longer leash than his predecessors given his budding resume at such a young age, but at some point Chelsea management needs to recognize the manager is essentially digging the club a massive hole that may be too steep for it to climb out of quickly.

The stakes could not be higher for Chelsea at the moment. The club is fighting for its Champions League life, with Tuesday's opening leg at Napoli as well as its battle for fourth place in the Premier League, which would grant the club a qualifying spot in the tournament. Should the Blues miss out on securing a spot in the prestigious competition, they can kiss potential summer signings and additional revenue goodbye.

"I'm really confident about next year," the manager went on to say in addressing the media on Monday. "That doesn't take any responsibility for what's happening now, but we had a three-year project to change not only the team, but the culture and structure of the club."

Villas-Boas can write his own ticket if he leads the Blues to Champions League glory this season, but at Stamford Bridge, a manager does not get to years two and three of his contract unless he finds success in year one.