When a Chelsea fan fondly reminisces back to the simpler times for Chelsea in 2005 where everything they did turned to gold under Jose Mourinho, one fact that remains in the the club's history is linked to the defenders.
To concede just 15 goals in a 38-game Premier League season is something that will simply never be repeated. It requires discipline, quality and most importantly, Jose Mourinho.
In that season, the back five were at the front of the queue when it came to handing out praise. That back five consisted of Petr Cech, Ricardo Carvalho, John Terry, Ashley Cole and Paulo Ferreira. Eight years later, four of the five still remain at Stamford Bridge.
Many defenders have come through to Chelsea and passed through the exit doors: Alex, Jose Bosingwa, Jeffrey Bruma (on loan) and Slobodan Rajkovic.
Yet, Chelsea's defence has been called into question in recent years as their strength and depth has decreased, and the stability at the club has become non-existent.
Being objective, nine managers in as many years is likely to destabilize the tactics the defence have to work on, with Andre Villas-Boas opting for a high defensive line during his short stint as Chelsea manager, while predecessors Guus Hiddink and Mourinho led with a more deep and organised approach.
The Blues boast one of the best defensive records in the league, but how exactly have their defenders fared this season?
John Terry has probably had more to deal with off the pitch than on it during his eventful career, but you have to admire the 31-year-old for how he deals with the criticism he receives.
Sacked as England captain last year in the wake of the Anton Ferdinand racism case, Terry is welcomed to every Premier League game away from Stamford Bridge with a chorus of boos.
Yet, the Barking-born defender, who made his Chelsea debut in in October 1998, gets on with his task of defending his team's goal with last-ditch defending and great organisational skills. And still adored by the club's fans, his captaincy at Chelsea has never been in doubt.
This season has been a hiccup in Terry's career; he received a four-game ban for his racist comments and then was hit with a knee injury which has kept him out for the best part of three months.
His performance against Brentford in the FA Cup Fourth Round highlighted his fall from grace, looking out-of-sorts as he struggled to deal with the League One's side attackers.
Gradually, Rafa Benitez has edged Terry back into the first-team action. It could be a while, however, until we see the defender back to his usual self.
They usually say that world class footballers have one season where they break through onto something spectacular.
Arguably, Lionel Messi is one who breaks that tradition, seeing as he tends to break just about every record that can be broken.
But look at his Ballon d'Or rival Cristiano Ronaldo. His haul of 42 goals in a season for Manchester United gave him the recognition he needed to go on to earn an £80 million move to Real Madrid and score an average of a goal a game since his move three-and-a-half years ago.
David Luiz is in the middle of his breakthrough season right now, with the 25-year-old Brazilian finally showing the form which explains why Chelsea paid Portuguese giants Benfica £21 million for his signature.
His pace and reading of the game enable him to snuff out the opposition's attacking moves, although this can lead him to being caught out, especially when he plays alongside Branislav Ivanovic or Gary Cahill, who tend to surge up field.
His passion for the game is always evident, especially when Chelsea lost in the final of the Club World Cup when Luiz was found kneeling on the floor, filled with emotion. And it's this passion which allows him to become a leader on the pitch.
Gary Neville once described Luiz as "a Playstation player controlled by a 10-year-old" and clearly, it was a comment made with a sense of naivety, but if anything, it seems to have spurred on the former Vitoria defender in pursuing the top level of his game.
At times, he can be key for Chelsea. And that's certainly been reflected in his performances this season.
It's hard to believe that a player of Branislav Ivanovic's influence and caliber almost walked out of Stamford Bridge without making a single appearance.
The Serbia international made a £9 million move to Chelsea in January 2008 from Lokomotiv Moscow but endured a difficult first year at the club, not making a single appearance until Luiz Felipe Scolari took charge of the West London club.
At that time, Ivanovic was on the verge of a loan move, with Juventus and AC Milan, keen admirers of the former OFK Beograd defender. However, Scolari blocked the move and assured him that he had a role to play at the club. And since then, he has never looked back.
It's not just his defending that has impressed Chelsea fans though. Twelve goals for the club in 133 appearances is not a bad return, and the most notable was his winner in the club's 5-4 aggregate win over Napoli in the Champions League last season, which set them on their way to winning the competition in May 2012.
His transition from center back to the right-hand side of defence was a decent choice. Although under Roberto Di Matteo and now Rafa Benitez, Ivanovic has been used as a spare center back.
Unfortunately for the 29-year-old, his two errors made against Swansea in the League Cup semi-final were costly enough to send the club crashing out of the competition.
Nevertheless, it was a rare blip in a solid season for Ivanovic, and if he continues to be a consistent performer, his place in the defence should not be under threat any time soon.
I have already had the opportunity to analyze Gary Cahill's performances so far this season, so any of you familiar with my work will know how I feel about the England center back.
Either way, if you're expecting me to wax lyrical about someone who Chelsea paid £7 million for just over a year ago, then you're incorrect. Equally, I'm not about to criticize him either.
And that is where Cahill fits: right in the middle.
His performances are rarely ever superb or poor, rather he is either slightly below-par or above average. A solid defensive performance in Chelsea's 2-0 defeat at Manchester City in particular highlighted this.
His last-ditch blocking is at times sensational. However, if you are a player who knows how Cahill plays, it's easy to get past him.
For example, Yaya Toure's opening goal consisted of a brilliant effort that was heading towards the outstretched hand of Petr Cech before Cahill's attempted block diverted the ball beyond the goalkeeper's reach and into the net.
In some ways, Cahill tries too hard at times. When in possession of the ball in his own half, he tends to look for the "Hollywood" long ball, even when a simple pass is open to a teammate. Chelsea concedes possession and their main problem is playing without the ball.
There's no doubt that on his day he is capable of being a key player for the Blues, but you would be a brave man to put him ahead of the likes of John Terry and David Luiz.
You can boo Ashley Cole, if you really want. You can frustrate him and try to get him sent off. You can even accuse him of being motivated by money.
You cannot, however, deny the fact that wherever Cole goes, he experiences success. Oh, and that he is one of the greatest left backs of all time.
Seven FA Cup winner medals, three Premier League titles, one Champions League winner medal and two runners-up medals add to the collection for his trophy cabinet. Not too bad, Ashley.
It did seem that Cole would be departing at the end of the season, with Chelsea refusing to budge on their one-year extension contract offer. And after being linked with a move to join former boss Carlo Ancelotti at Paris Saint-Germain, he signed the deal to stay at Stamford Bridge until at least June 2014.
Despite his advancing years, the former Arsenal left back still has the pace and stamina to race down the touchline and support both the attack and defence. His performances have seen him named Chelsea's Player of the Year in two occasions, highlighting his worth to the team.
Under Rafa Benitez, performances have come down slightly, and the Spaniard is known to prefer Ryan Bertrand when it comes to lesser known opposition, such as in their 1-0 defeat to Steaua Bucharest.
Ashley Cole himself will know that in comparison to last season, it's not been his finest campaign. But the refreshing point about the 32-year-old is that he will strive to better his performances, and that can only be good for Chelsea.
There were doubts about whether Cesar Azpilicueta could adapt to the physical demands of English football, but the Spaniard has enjoyed an impressive start to his Chelsea career.
Making a £7 million move from financially-stricken Marseille last summer, Azpilicueta has shown signs of improvement already in his six months at Stamford Bridge.
He has quickly made the right back position his own, bombing up and down the right-hand side with speed and enthusiasm.
Eighteen Premier League appearances have seen him create four goals although he is yet to find the net for his new club. But that is not the former Osasuna man's job.
Rafa Benitez may not take credit for too much during his time at Chelsea, but one thing he can be happy about is overseeing Azpilicueta's first cap for Spain, with the 23-year-old's performances improving under the tactician.
It is early days in the career for Azpilicueta; he is far from a finished article and has to iron out any positioning errors. Nevertheless, the Spaniard is developing his attributes both defensively and offensively, and that should be recognized by fans.
Because if Vicente Del Bosque, a World Cup winning coach, can, so can you.