With all its ups and downs, stability and unpredictability, and ecstasy and devastation, 2015 was certainly an unforgettable year for Chelsea. The Blues went from devastation in Europe to triumph in England in the first half of the year, and then from disappointment to desperation in the latter half. The roller coaster of a year was marked by their dominant title-winning campaign and their flimsy title defence, eventually culminating in the monumentally significant dismissal of Jose Mourinho, arguably the best manager Chelsea had ever had.

Champions League exit

The Blues started out the year with a disappointing exit from the Champions League in the knockout stages. Paris Saint-Germain came back from behind twice to end the second leg with a 2-2 draw. Due to the away goals rule, the French side advanced to the quarterfinals for the third straight season, leaving Chelsea to focus on their Premier League campaign.

The match was marked by tension as several players almost came to blows. Former Blue David Luiz and Diego Costa were at each other’s throats throughout the match, the former often trying to provoke the latter by goading him in his native Portuguese.

Tempers flared as Swedish powerhouse Zlatan Ibrahimovic saw straight red for a clumsy tackle on Oscar, reducing the French side to 10 men. It was one of many questionable decisions made by referee Bjorn Kuipers that night, but despite the disadvantage, PSG’s Brazilian defenders Luiz and Thiago Silva cancelled out goals from Gary Cahill and Eden Hazard, respectively, to bring the match to a draw.

Despite all his accomplishments with Chelsea, Mourinho had never won the Champions League with the English side, so their exit was particularly devastating for him as he will never again get the chance.

Premier League glory

The despair in Europe didn’t take away from the glory at home, however, as Chelsea ended a spectacular 2014-15 Premier League season with another title. Chelsea were truly dominant during their title winning campaign, losing only three games and staying at the top of the table from the start of the season.

Although the Blues were accused of unentertaining football during their title run, their “boring” style of play was efficient and effective enough to lead them to success.

Eden Hazard’s goal in Chelsea’s 1-0 victory at home against Crystal Palace clinched their 2014/15 Premier League title, ensuring that the Blues were too far ahead of everyone to be caught, and they ended the season with 87 points. In addition, Hazard won PFA Player of the Year, and Mourinho, who had led Chelsea to three Premier League titles, won Manager of the Year.

A sour end to the second spell.
A sour end to the second spell.

A horrific start

An unimpressive preseason and a disconcerting loss in the FA Community Shield to bitter rivals Arsenal foreshadowed Chelsea’s unanticipated misfortune in the new season.

The Blues kicked off the season with a 2-2 draw to Swansea City in which the Blues looked neither dominant nor cohesive, mere shadows of their old selves. The following week, the Blues lost at the Etihad to last season's runners-up. From there, it was all downhill as the results got worse and worse until eventually becoming became the worst start to a title defence in Premier League history and Mourinho’s worst start to a season.

By the end of 2015, Chelsea were sitting at 14th in the table with 20 points in 19 games, just three points above the relegation zone. While Chelsea have been flirting with the line between relegation and safety, the club has been in denial of the seemingly impossible: that Chelsea could be facing the relegation battle rather than the title race.

Jose Mourinho's departure

During his two spells at Chelsea, Mourinho accomplished much with the club. He led Chelsea to two back-to-back Premier League titles, the League Cup twice, and the FA Cup once in his first stint at the club, and he accomplished winning both the title and the League Cup once more after he returned. Over the course of his time at the club, he earned the Manager of the Season award thrice.

However, things started to turn sour for Mourinho during the summer. After very little transfer activity, a few losses, not to mention their FA Community Shield loss to Arsenal in August, and their less-than-dominant form in the preseason, some wondered whether or not Chelsea could retain the title. However, speculation was low.

The beginning of Chelsea’s 2015/16 Premier League campaign was disappointing, however, as Chelsea suffered their worst start to a title defence, and Mourinho went through by far the worst period of his career.

Underperforming players, the controversial dismissal of first-team doctor Eva Carneiro, his divisive comments and decreasing confidence, and the growing speculation that he had lost the dressing room were all factors that led to Mourinho’s demise at Chelsea. The Portuguese with his record and experience could have undoubtedly led Chelsea out of the hole they were stuck in in the long term, but with no immediate end to the team’s poor run in sight, the best option to gain short-term success seemed clear: Mourinho had to go.

Guus Hiddink's takeover

Enter Guus Hiddink. The former Russia, Turkey, and Netherlands manager had had a previous spell at Chelsea in 2009, leading the Blues to an FA Cup and a Champions League semifinal. The Dutchman had a win ratio of 73% in 22 games, the highest in Chelsea’s history, and is a well-experienced and clever manager. In addition, he formed strong bonds with the players during his first stint as interim manager, and the fans remember him fondly.

However, since he departed Chelsea, he has not accomplished anything much. Recent failures while presiding over the Russians, the Turks, and the Dutch have revealed that, although once a great manager, Hiddink’s star has faded.

Hiddink will be Chelsea's interim manager until the end of the season. The club has high hopes that he can turn their season around and improve the team in ways Mourinho would never have attempted, such as calling up the youth and relying on a wide selection of players. Despite his recent decline, the club and the fans have confidence in Hiddink that he can make a top four finish a reality for the Blues.