Chelsea have become one of the top football clubs in Europe since the turn of the century, and this has seen them become a serious destination for talented players across the world.
Superstars like Didier Drogba and Micheal Ballack are surely the pick from a host of internationals who have chosen to ply their trade for Chelsea during the first decade of the century.
Today, we take a look at five of the best signings by the Blues from the last decade and their impact on the team. Just including five picks means a host of Chelsea players who have impressed have miss out on the final cut.
The likes of Willian, Cesc Fabregas and Juan Mata are among some of the elite players who find themselves in the honorable mentions for this list.
Five best Chelsea signings of the decade:
#5: Thibaut Courtois
Thibault Courtois might have become a legend for Chelsea in the mold of his predecessor Petr Cech had it not been for his unceremonious exit from Stamford Bridge last season.
The Belgian, signed by Chelsea from Genk for a reported € 9 million in 2011, emerged as one of the most promising goalkeeping prospects in Europe after starring for the Belgian club in their title-winning campaign.
Having spent three years on loan at Atletico Madrid where he perfected his craft under Simeone, Courtois was recalled by Chelsea as Jose Mourinho chose to start him over veteran Petr Cech. Courtois would go on to win two Premier League titles during his four-year stint in the Cheleas first team while establishing himself as one of the best custodians in the world.
The Belgian's departure from Chelsea left a gaping hole in the first team, and his subsequent replacement, Kepa Arizzabalaga, has not been up to Courtois' standard. Courtois has always conceded less than a goal a game throughout his career and conceded 121 goals in 126 Premier League appearances for Chelsea.
Courtois also missed out on a personal record when he left Chelsea as he was just one short of the half-century clean sheet milestones mark in the Premier League.
In short, Courtois was a very good signing for Chelsea. While he could have fetched much more than £35 million for which Real Madrid eventually bought him for, his sale still meant financial profit for Chelsea. But Courtois deserves to be on this list based on his performances alone.
#4: Diego Costa
Always the maverick, the Brazilian-born Spanish international, Diego Costa was a fixture in the Chelsea line-up during his three seasons with the London club. Costa played a huge part as Chelsea won two Premier League titles under Mourinho and Conte before his relationship soured with the latter.
Diego Costa had joined Chelea from Atletico Madrid after leading his former side to their first La Liga title since 1996 in the 2013-14 season. He had also led his side to the finals of the UEFA Champions League for the first time since 1974 as he scored eight goals during that campaign.
Costa became an instant Chelsea hero following his goal-scoring exploits for the club. He holds the record for most goals by a player after their first four matches in the Premier League.
He would go on to contribute 20 goals in his debut campaign as Chelsea won their first Premier League title under Carlo Ancelotti since the 2010 season .
Chelsea fans also loved Costa for his incredible record against Arsenal as he scored three goals against them in six matches while also managing to get inside the head of their players.
In a meeting between the London rivals during the 2015/16 season at Stamford Bridge, Costa caused havoc for Arsenal as he managed to get Gabriel sent off after some provocation. Costa would repeat the trick at the Emirates in the reverse fixture while scoring a goal as he provoked a last-man challenge from Per Mertesacker for which the German saw a red.
The temperamental striker did very well for Chelsea before his bust-up with Conte. He scored 52 goals in 89 Premier League appearances. Bought for just £32 million, Costa's name deserves to be mentioned considering his massive impact as well as the relatively cheap fee for a player of his quality.
#3: N Golo' Kante
The shy Frenchman, N'Golo Kante, was a key player in Leicester City's fairytale Premier League-winning season in 2015-16. He has since become a fan favourite for Chelsea during his three-and-a-half-year stay at Stamford Bridge.
After joining for a fee of £ 32 million, Kante was voted the PFA Player of the Year for his exploits in midfield as Chelsea were crowned champions during the Frenchman's first season at the club.
Kante has been a dominant presence in the midfield for Chelsea despite playing under three different managers in his four seasons in London. He has made 160 Premier League appearances for Chesea during this period.
Kante, who is mostly known for his defensive intelligence, has also shown that he can play further forward when needed as seen under Maurizio Sarri last season. His most successful season at the club, however, was surely his first, when under Antonio Conte and alongside Nemanja Matic, Chelsea brought the Premier League title back to London.
Kante averaged a career-high 2.40 points per game at the time as he firmly established himself as a fan favourite at Stamford Bridge.
#2: Cesar Azpillicueta
Cesar Azpilicueta has been fabulous for Chelsea during his eight-year spell at Stamford Bridge that has seen him accumulate 374 appearances in all competitions for the club.
“Azpilicueta is the kind of player I like a lot. I think a team of 11 Azpilicuetas probably could win the Champions League because football is not just about pure talent"- Jose Mourinho on Cesar Azpilicueta.
Bought by Chelsea for a paltry sum of a reported £7 million, Azpilicueta has definitely exceeded every expectation when he joined Chelsea after the club's Champions League win in 2012.
His hard work and endeavour has seen him become a fixture under different managers from the likes of Rafael Benitez and Jose Mourinho to the current manager Frank Lampard.
Azpilicueta played as the right-sided centre-back in a back three under Antonio Conte during Chelsea's victorious Premier League campaign in 2016-17, playing every minute of that season. Being a regular in a title-winning team meant that he managed to collect 2.45 points per game in 38 matches played, which is an incredible feat.
The Spaniard, who joined Chelsea as a young player, has slowly but surely matured into a leader as monumental figures like John Terry and Gary Cahill waded into the sunset. Having filled the role of vice-captain for two years since Terry's departure, Azpilicueta was anointed as Chelsea captain before the start of this season by Frank Lampard.
#1: Eden Hazard
Nobody has defined Chelsea more than Eden Hazard in the decade gone by.
The mercurial Belgian, who joined the London club for £32 million from Lille back in 2012, was the talisman at Chelsea, serving as the club's creative heartbeat. Hazard's pace, acceleration and dribbling skills made him one of the toughest players to play against in the Premier League during his seven-year stay in England.
Having made 352 appearances in all competitions for Chelsea, Hazard scored 110 goals while also contributing 92 assists, thereby establishing himself as one of Chelsea’s modern-day icons.
While Hazard was always considered as one of the most promising youth prospects of his generation, it was at Chelsea where he really bloomed into a world-class player. Things might have ended sourly between Mourinho and Hazard but it was under the Portuguese tactician's guidance that Hazard came to prominence as an elite player.
"He is already a top player and his evolution has been fantastic. He is still very young and he can become the best player in the world."- Mourinho on Hazard
The Belgian forged his way out of Chelsea in the most respectable manner unlike his compatriot Courtois, after leading Chelsea to last year's UEFA Europa League title.