When Jurgen Klopp was appointed as the Liverpool boss, it seemed that the biggest lift he was going to give the club was one to do with mentality and morale. The exact quality of the squad left behind by his predecessor Brendan Rodgers was unclear.

The players could perhaps best be described as inconsistent – better than the greatest percentage in the league but lacking that little bit extra to really break into the elite few who enjoy Champions League football. Much like the squad itself.

Ultimately, Liverpool finished 6th in 2014-15 – a position perfectly consistent with the above description. At the same time, across the Channel in Germany, Jurgen Klopp had rescued Borussia Dortmund’s disastrous season to finish 7th in the Bundesliga.

But significantly, Dortmund also reached the final of the domestic cup and qualified for the Europa League. Klopp’s side had been crippled by injuries, but he was able to inspire enough belief in his players to rally around for a respectable second half of the season. And that’s where his appeal lies. Liverpool’s experiences this season have proved that The Klopp Effect is very real.

Football and psychology normally mix well together. For Klopp they certainly do. Liverpool only picked up 5 points in 6 games against last season’s top four. This season, however, Liverpool have collected 11 points against the same four teams – with Chelsea still to play at Anfield. Brendan Rodgers is responsible for one of those points (a 0-0 draw at the Emirates in August). Klopp, ten of them.

Indeed, Klopp’s big game mentality has displayed a trustworthiness not seen since the days of Rafa Benitez and Gerard Houllier before him. But what sets the German apart from Liverpool’s other continental stewards is bravado. Whereas Houllier and Benitez believed in a rigid, defensively firm approach, Klopp prefers speed and intensity. And it has produced impressive results.

This season, Liverpool have scored seven against Manchester City in two games, letting in only one. They have stuck three exquisite goals apiece against Arsenal and Chelsea, the latter being played at Stamford Bridge no less. Liverpool have knocked six past Southampton in the League Cup and five in two legs against a Borussia Dortmund side that had conceded only six in the tournament till that point.

Frequent showers of goals against big names equip the players with a confidence that encourages the Liverpool fraternity that anything can happen. Indeed, last minute goals and fight backs are now key parts of a collective Liverpool mentality that seemed weak and fragile only a year ago. Improbable wins and rescues like Arsenal, Norwich and now Dortmund are happening so frequently as to achieve all the novelty of sunrise.

On a more practical level, Liverpool are also learning the benefits of having a manager with European and cup experience. Knockout football is an entirely different kettle of fish, as Brendan Rodgers learnt to his cost. No progress beyond the Europa League Round of 32, only one win from six in his Champions League group and two domestic semi-finals in three years at the club did not paint a very flattering picture.

Klopp’s intelligent game management is showing. A final in his first season (lost only on penalties) and at the very least a European semi-final suggests Klopp has the acumen to successfully negotiate a series of one-off ties. Clean sheets and defensive strength are important in these conditions; while the Anfield leg of the Borussia Dortmund encounter was clearly an anomaly of a football game, Liverpool had conceded only twice in five previous knockout stage games. The only undefeated team left in Europe this season, Liverpool now face Villarreal in the semi-finals, and could possibly do the unthinkable should Klopp maintain these levels of concentration.

The key to this defensive strength has been the resurrection of Dejan Lovren under Klopp. Now one half of a central defensive partnership with Mamadou Sakho, Lovren has seen a dramatic turnaround in form, and his winning goal against Dortmund was memorable for its symbolic as well as sporting importance.

Klopp’s attack now bears a fluid, exciting character. Philippe Coutinho (11 goals so far), Roberto Firmino (10 goals) and Divock Origi teetering on double figures himself (9), have personified The Klopp Effect on the pitch – instead of fluttery, inconsistent luxury players, Liverpool now have a trio of intense, focused and effective footballers who deliver consistently on the big occasions.

At Borussia Dortmund, Klopp carefully built a side of outstanding talent and temperament, reinforcing a commitment to finding the right kind of player for the system. The Klopp Effect has re-energised Liverpool’s mentality and equipped them better tactically, but recruitment is the next big challenge for the German to prove that The Klopp Effect is lasting and not temporary.