Four winters ago, Niko Kovac, now the manager of Bayern Munich, decided to spend the early weeks of the year studying one of the greats of his profession. He was still learning as a manager and he contacted Jurgen Klopp, asking if he could observe mid-season training at Borussia Dortmund. Klopp, now of Liverpool, said yes. He knew Kovac a little, and knew his brother Robert, who works as Niko’s assistant, even better. When Klopp had first arrived at Dortmund, way back in the summer of 2008 as an ambitious, up-and-coming 40-year-old manager, Robert Kovac was the club’s imposing central defender, owner of close to 80 caps for Croatia. One one of Klopp’s first bold decisions was to point him towards the exit door, replacing him with a then 20-year-old Mats Hummels, part of Klopp’s dynamic and transformative programme for making Dortmund younger and more energetic. Neither Kovac bore a long grudge and Robert will greet the now Liverpool manager warmly at Anfield on Tuesday night. Niko Kovac, meanwhile, will be aware that whatever he does tactically, motivationally and while standing in the technical area through the first 90 minutes of their Uefa Champions League duel, he is bound to be compared with Klopp. It is the fate of most managers who have developed promisingly in the Bundesliga to be measured up against Klopp, the best manager German club football has produced this century. Klopp might well have become a Bayern head coach. He joined Dortmund at a time the Munich giants were also looking for new manager, and indeed Bayern contacted Klopp, but chose Jurgen Klinsmann instead. Klinsmann would be sacked within nine months, and Bayern have since changed their manager another eight times before appointing Kovac last year. Klopp, meanwhile, stayed at Dortmund for seven exhilarating seasons, and, it might be argued, turned himself into the biggest obstacle to Bayern’s domestic domination. He twice led Dortmund to the Bundesliga title, in 2011 and 2012, and the second time completed a Double with a 5-2 demolition of Bayern in the German Cup final. He took Dortmund to a Champions League final too, narrowly losing it to Bayern in 2013. At which point Bayern began to regularly headhunt Dortmund players, much to Klopp’s anger, although time has healed some of the wounds from what at that time became a fractious relationship. Uli Hoeness, the Bayern president, said ahead of the trip to Anfield: “I have great admiration for Klopp.” It was Hoeness who 11 years ago first ventured the idea of Klopp managing Bayern and then stepped back, thinking the appointment too much of a risk. In many ways Bayern finally took that sort of risk on Kovac, who although he had managed Croatia for a spell, had Bundesliga coaching experience limited to under two years at Eintracht Frankfurt when Bayern offered him the post. When Hoeness approached Klopp, he too was still a relative novice, having managed only two seasons in the German top flight. Kovac turned 47 last October, by which time he was already coming to know the unique pressures of his job. He started well at Bayern, inherited a gifted set of players - though few significant summer newcomers - and mostly they played like a team who have won the previous six league titles. The Kovac era began with seven wins out of seven. Then came the hiccups: a four-match run featuring two losses and no victories. Since then, Kovac has been in a game of catch-up in pursuit of this season’s rejuvenated Dortmund in what is becoming a scintillating Bundesliga title-race. Bayern can look brittle, and Kovac once more addressed persistent shortcomings after Friday night’s 3-2 win against Augsburg, a match in which the champions had trailed twice in the first half. “Every shot looked it was going to be a goal,” he said. His Bayern, with Hummels their senior centre-half, have let in over a goal per game, across competitions, so far. On Tuesday night, Kovac’s creaky back line confronts Klopp’s carefully choreographed trio of strikers, Mohamed Salah, Sadio Mane and Roberto Firmino, and although Bayern will take some confidence from the fact Virgil Van Dijk misses the first leg of the Champions League last-16 bout with suspension, Kovac would be justified in privately feeling that to leave Anfield with a draw would be regarded as a small triumph. And if he can come through the 90 minutes without his employers thinking regretfully back to the time when they carelessly discarded the young Klopp, he will have won an important battle.