Some departures you see coming from miles away. Others hit you like a brick through the window at three in the morning.

Eight years ago today, Liverpool confirmed that assistant manager Zeljko Buvac would not work with the first team for the remainder of the 2017-18 season. Just like that. No fanfare, no lengthy explanations, just a brief statement citing 'personal reasons'.

The timing was brutal. Two days before the crucial Champions League semi-final second leg in Rome against Roma. The man Klopp affectionately called 'The Brain' had simply walked away from the biggest moment of their Liverpool project so far.

Buvac wasn't just any assistant. He'd been Klopp's shadow for 17 years, following him from Mainz to Borussia Dortmund and then to Anfield. They were a partnership forged in German football's lower leagues, tested in Champions League finals, and seemingly unbreakable.

Yet sources suggested the Bosnian had become increasingly distant and withdrawn. The 0-0 draw with Stoke City at Anfield on April 28, 2018, proved to be his final match. The 64-year-old never returned to Anfield, and speculation that he'd never come back proved accurate.

Liverpool fans had every right to be worried. History suggested assistant manager departures spelled trouble. The club was never quite the same after Gerard Houllier lost Patrice Bergues in 2001, or when Pako Ayesteran left Rafa Benitez's side in 2007.

But this time was different. This time, Klopp proved his greatest strength isn't reading the game but reading people and situations.

Yes, Liverpool lost the 2018 Champions League final 3-1 to Real Madrid in Kiev. But from that moment, they became virtually unstoppable. The 2019 Champions League triumph in Madrid against Tottenham, beating them 2-0. The UEFA Super Cup. The FIFA Club World Cup. And finally, the prize that mattered most to supporters: the Premier League title.

The key to this transformation was Pep Lijnders. The Dutchman returned to Anfield in June 2018 after a stint managing in Holland, but only became official assistant manager in January 2019 when Buvac formally left his post.

According to German football expert Raphael Honigstein's updated biography on Klopp, the split wasn't entirely surprising to those close to the situation. Buvac had become unhappy with Lijnders' growing influence before the Dutchman's temporary departure to Holland.

"Buvac gave the impression that he wasn't happy with the increasing influence of the fourth assistant coach Pepijn Lijnders," Honigstein wrote. "The relationship between Buvac and Klopp had survived, but both could simply no longer work together."

While Buvac was linked with the Arsenal job following Arsene Wenger's departure, he didn't return to football until February 2020, taking a sporting director role at Dynamo Moscow in Russia, where he remains.

By then, Klopp and Liverpool had already proved they could not just survive without 'The Brain', but actually improve. It's a testament to Klopp's adaptability and his understanding that even the strongest partnerships sometimes reach their natural end.

Both men later reflected on their split with surprising candour. "By and large for all these 18 years I felt myself in charge," Buvac told Nobel. "I did all the same work, I just didn't have that much attention. Everyone asks how and why, but people live together for 30 years and then they break up. It happens."

Klopp's assessment was equally pragmatic. Speaking to BT Sport's Boot Room Boys, he explained: "I worked together for a long time with Zeljko Buvac, who was a more experienced coach than I was when we started. We worked very close for a long time together and then it didn't work out anymore and we brought in Lijnders and Vitor now. They are like energisers, they are the next generation."

The German's description of his new assistants reveals everything about why the transition worked. "They have a different view, they are like training machines. I say 'I want to play like this' and they shoot like 25 sessions out of the hip like, 'which one do you want?' They keep you really young and on your toes."

What happened eight years ago wasn't just about losing an assistant manager. It was about Klopp proving that great leaders don't just survive disruption, they use it to evolve. The partnership with Buvac had run its course, but the manager's ability to rebuild and refresh kept Liverpool moving forward.

As Klopp himself put it: "I would be nowhere near where I am without the people over the years around me. But the people around me know that they are only here because I am around as well and together we are pretty okay."

Pretty okay indeed. And perhaps that unexpected shake-up eight years ago was exactly what Liverpool needed to reach the summit.