In the summer of 2014, Chelsea brought Brazilian-Spanish striker Diego Costa from Atlético Madrid to Stamford Bridge on a £32 million transfer as we looked to solve our woes of the previous three-and-a-half years at his position. With the support of Cesc Fàbregas, Eden Hazard and manager José Mourinho, Diego quickly became one of the Premier League's most lethal forwards, helping the Blues to the Premier League and the League Cup titles in his first season at the club.

However, the first half of his second season in England didn't go as expected. Diego's form, as well as the rest of the team's form fell heavily only three months after getting a domestic double, with the axe falling on Mourinho in December. His sacking and the re-introduction of former interim boss Guus Hiddink did turn our fortunes around somewhat, and helped Diego find his scoring boots once again.

Although Chelsea's current form on the pitch has really helped to push last season's results to the back of our minds, there's still a looming question on what lead the squad to the "palpable discord" of last season. And in an interview with former Barcelona player Simão Sabrosa for Portuguese TV network Sport TV, Diego spoke about his relationship with Mourinho, admitting that he made a few mistakes when working with the Portuguese boss.

"Obviously, working with [José] Mourinho puts you in a great position. These years with him were good. The last year [wasn't], since we weren't getting results on the pitch and things weren't working as expected by everyone. And some stuff happened, but nothing too serious." "My relationship with Mourinho... I say this to everyone, 'every person has a good and a bad side'. But Mourinho and I had a good relationship. He always joked with us, gave us plenty of freedom, he talked with us... He was someone who also listened a lot." "There were a lot of good things. So when I look back, there were a few moments that I made mistakes; plays which I shouldn't have made given all the love and respect he gave to me" "Thus, I have nothing against him. If there is someone who should have something against someone is Mourinho himself [towards me]. And I believe he doesn't have that. I had a good rapport with him."

One moment that made headlines around the globe and seemingly summarised the relationship between Mourinho and his players towards the end of his second stint was the bib incident, which happened on November 29th of last year during the game against Tottenham in the Premier League. At the time, a clearly frustrated Diego threw his pink bib up in the air after going back to the bench following a warm-up routine that amounted to nothing since Mourinho chose Kenedy and Ruben Loftus-Cheek to take the pitch instead of our then not-so-prolific striker.

When prompted with the video by Sabrosa, the mildly annoyed Diego explained what lead him to his action, and what ensued after with Mourinho.

"This video... The moment I first saw the video I thought 'thank God it didn't hit him'. Imagine what would happen if it did?" "At that time I was furious, because at that day was my daughter's birthday. And it was also the first time he had me on the bench [throughout a game] — which is normal, things like these happen since I wasn't playing too well. It was an option he made. But I had this expectation that I would enter the pitch." "I went to do warm-ups, thinking that he would put me in the game... And we always want to play. So when I realised that I wasn't going to play since he had made another substitution, I took the bib and threw it high as an act of frustration." "After that I spoke to him, and said that it wasn't my intention to hit him with the bib. He knew that I was enraged, and I apologised because the whole affair was a bit ugly." "The press here [in England] is very prone to speak beyond reason, saying that I wanted to hit him, but that didn't happen. I explained my reaction to him, he accepted my apologies and everything was OK." -Diego Costa; Source: Sport TV via ESPN Brasil

While it doesn't explain why last season went so awry, Diego's explanation does provide closure for this one particular incident. Diego's a fiery character and he seemed to have a similarly frustrated reaction at Conte earlier this season as well. But that issue was quickly smoothed over, with Chelsea continuing to win and Costa continuing to lead the league in goals. May those long continue.

Meanwhile, our search for a definitive answer for what wen wrong last season — if there is one in the first place — continues...