Jurgen Klopp and Louis van Gaal will go head to head this Sunday when Liverpool host Manchester United, resuming a rivalry that briefly dictated the top of the Bundesliga.
As former managers of Borussia Dortmund and Bayern Munich respectively, Klopp and Van Gaal will be fully prepared for combatting each others strengths after their four previous meetings in Germany.
Both Liverpool and United experienced frustrating 3-3 draws in the mid-week fixtures and both will be desperately seeking to build momentum, as we reach the business end of the Premier League season.
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September 2009 - Borussia Dortmund 1-5 Bayern Munich
In Van Gaal's first game against Dortmund, Bayern swept to an emphatic victory. Though Dortmund centre-back Mats Hummels opened the scoring, Van Gaal's side hit back in style with current Manchester United midfielder Bastian Schweinsteiger scoring the crucial second goal.
February 2010 - Bayern Munich 3-1 Borussia Dortmund
Once again Klopp's side enjoyed a brighter start; taking the early in the first half. Again though Bayern's quality soon told with goals from Mark van Bommel, Arjen Robben and Mario Gomez. Bayern would go on to win the double later that season, with only Jose Mourinho's Inter Milan denying them the Champions League too.
October 2010 - Borussia Dortmund 2-0 Bayern Munich
Things were to be very different for both Van Gaal and Bayern in the following season. Lucas Barrios opened the scoring for Dortmund before an exquisite free-kick from Nuri Sahin secured all three points for the home side.
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February 2011 - Bayern Munich 1-3 Dortmund
A result that not only signified a changing of the guard but also spelt the end for Van Gaal at the Allianz Arena. Goals from Barrios, Sahin and Hummels sealed the win and propelled Dortmund onto their first of back-to-back Bundesliga titles later that year. Van Gaal was sacked in April with the club lying fourth at the time.
Klopp is still imposing his renowned Gegenpressing on Liverpool however, he has already recorded some significant scalps in his fleeting Premier League career.
Liverpool have thrived in the bigger games away from home, against sides who are comfortable to have the ball with the onus to attack.
The 3-1 win at Stamford Bridge and the even more remarkable, 4-1 victory at Manchester City, were both born out of Liverpool's willingness to harass the opposition and regain possession high up the pitch.
In both games Klopp chose to play without a striker - Daniel Sturridge remains injured whilst the German manager seemingly remains unconvinced by Christian Benteke - and Roberto Firminio, on the back of scoring twice against Arsenal on Wednesday, will in all likelihood be tasked with the false nine role once more.
Liverpool are yet to transfer their impressive away form into their performances at Anfield; however, with the top four still a possibility, there will be no better time to do that, than against their arch rivals.
In contrast whereas Klopp's style of football and touchline persona are characterised by energy and a hint of madness, watching United under Van Gaal this season has often proved to be painful viewing.
Van Gaal's side have failed to score in the first-half of 12 of their games in all competitions this season and endured a dismal six 0-0 draws.
Though there seemed to be an increased willingness to attack against Newcastle United on Tuesday, with captain Wayne Rooney looking particularly rejuvenated, United have been consistently unwilling to take risks this year with their slow, possession-based football attracting significant criticism from former players such as Paul Scholes.
Van Gaal has a perfect league record against Liverpool so far - he won three out of three against Klopp's predecessor Brendan Rodgers - and may be tempted to go for it to expose the Reds' defensive flaws.
Mamadou Sakho and Kolo Toure were both unconvincing against Arsenal, whilst Anthony Martial tore Liverpool's defence to shreds, for his debut goal in the reverse fixture back in September.
Only results, delivered in an entertaining manner, will provide United's manager with any short-term security, especially with Mourinho still available, implying this Sunday's showdown could well prove to be the decider in the Klopp, Van Gaal rivalry.
Who do you think will come out on top this Sunday, Klopp or Van Gaal? Have your say in the comment box below!