What has been Roman Abramovich's best decision as Chelsea owner?
In that time, the billionaire's every move at the club has been under close scrutiny in the media, with star players recruited and managers hired and fired in his pursuit of glory.
Chelsea has won three Premier League titles, the Champions League, four FA Cups and two League Cups since the Russian become owner. By that mark alone, it's been a successful 10 years at Stamford Bridge.
But what has been Abramovich's best decision? In no particular order, Bleacher Report takes a look at his top five.
Jose Mourinho is Chelsea's most successful manager.
Without Roman Abramovich, it doesn't need to be said Chelsea wouldn't have seen the likes of Didier Drogba, Petr Cech and Fernando Torres at Stamford Bridge. The Russian's billions have bankrolled the club's recruitment drive over the past decade, which has seen some of the world's best players arrive—with the club enjoying unprecedented levels of success.
Without the addition of Jose Mourinho, however, it's hard to say whether the Blues would have enjoyed such a trophy-laden decade. The Portuguese spent three years at Chelsea, arriving from Porto in 2004 having just lifted the Champions League trophy, and he continued that success in West London.
In his first season at Chelsea, Mourinho ended the club's 50-year wait for the league title and moulded the club into a European force.
Indeed, such was his impact, successive Chelsea managers have used his blueprint to mastermind their own glory at Stamford Bridge, thus ensuring his presence remains strong.
Mourinho's tactical nous and knowledge of the game has been just as important to Chelsea in the past 10 years as Abramovich's fortune. They formed a lethal partnership that threatened to dominate English and European football, so it's understandable Blues fans were so distraught when it came to an end.
But with all the signs seeming to suggest the pair may be about to reignite their partnership (via Rob Beasley, The Sun), could this be one decision Abramovich is set to repeat?
If so, it could be the greatest of them all.
Ashley Cole remains one of the world's finest defenders
He will win his 100th cap for England against Brazil this week and despite his aging years, Ashley Cole remains one of the world's finest defenders. It's why Chelsea's decision to renew his contract this season is perhaps one of the best signings the club has made in the Abramovich era.
His move to Chelsea in 2006 was surrounded by controversy, with accusations of the Blues "tapping" him up while under contract at Arsenal. Many onlookers also questioned the wisdom in the swap deal that saw William Gallas move in the other direction.
Well, seven years on and with Cole still a feature at Chelsea while Gallas has long departed the Emirates without a trophy to his name, that's one debate that has long been spent.
He has been an incredible servant for the club and his experience in the dressing room will only aid the likes of Ryan Bertrand's development.
Peter Kenyon brought a new business dynamic to Chelsea
It's an area many football fans tend to avoid discussing, but the business side of the game plays as big a role in the 21st century as the actual action on the field of play.
In appointing Peter Kenyon as chief executive in 2003, Roman Abramovich pulled off a masterstroke that gave the Blues an edge off the pitch, tapping into his commercial contacts to bring the club a considerable profile.
Kenyon had worked for Manchester United in a similar role and enjoyed great success as the club established itself as a global brand.
He was instrumental in Jose Mourinho's arrival, and the likes of kit manufacturer Adidas soon came on board at Chelsea when Kenyon was appointed. He also attracted a major new shirt sponsor in Samsung and both companies continue their relationship with the Blues, which is of huge financial benefit to the club.
It all seems a little tainted to be discussing business in a football context, but it's a reality of the game in the modern era. Fans can say what they will about those in positions such as Kenyon's—and now Ron Gourlay, who replaced him at Chelsea in 2009— but without a business-savvy CEO, many clubs struggle to compete in a game where commercial success is just as important as sporting triumphs.
The likes of Ron Harris have been welcomed back to Chelsea since Abramovich took over
Under Ken Bates, things had grown sour with Chelsea and the club's legends who had once served the team so well.
Many had been banned by the former chairman from attending matches at the stadium and were unwelcome at the club. Despite everything he had done for Chelsea—buying the club for £1 in the '80s before ridding it of debt—it was a considerable misjudgement on his part and effectively erased a significant part of Chelsea's history.
Roman Abramovich changed that when he purchased the club from Bates. The Russian was adamant he would build a successful future for Chelsea, which he has, but he has done so by celebrating the past and welcoming back heroes from the past.
The likes of former captain Ron Harris are now regulars at games once more, rubbing shoulders with the fans who idolized them in their pomp. But more significantly, in the Chelsea Past Players' Trust, the club has a thriving organisation that helps former players and employees in need of medical care.
Former MP Tony Banks, who died in 2006, was instrumental in getting the idea of the trust started, and since his passing, it has grown to become a key aspect of the club's relationship with its former players.
Abramovich's day-to-day involvement with the trust may be limited, but the Russian must take a measure of credit for reintegrating Chelsea's past players and allowing such organisations to grow and become of great benefit.
Roberto Di Matteo lifts the Champions League trophy
Say what you will about everything that has happened since Roberto Di Matteo was appointed Chelsea's caretaker manager in March 2012; it was an inspired appointment by Roman Abramovich.
The Blues were staring defeat in the face against Napoli in the Champions League after a 3-1 first-leg defeat, but the Italians visited Stamford Bridge three weeks later to face a revitalised outfit following the dismissal of Andre Villas-Boas.
Since their first meeting, Di Matteo had restored confidence in the Chelsea dressing room and they blew Napoli away, winning 4-1 to progress through to the quarterfinal.
Everything that followed was a fairy tale.
They defeated Barcelona 1-0 at home before an unbelievable 2-2 draw in the Nou Camp, while a penalty shootout victory over Bayern Munich gave them victory in the final. It was an amazing turnaround for a team that looked down and out, and Di Matteo was the man who orchestrated it.
In generations to come, it will not be Di Matteo's departure as Chelsea manager that followed six months after that night in Munich that will be discussed on the terraces. It will be the club's Champions League victory, and Abramovich deserves his share of the accolades in giving Di Matteo the manager's job, even if it did end on a sour note.