Jurgen Klopp was an average footballer.
He spent most of his career in the German second tier playing for Mainz 05.
But Klopp has had enjoyed more success since making the transition to a manager in 2001.
The German spent seven successful years at Mainz before moving to Dortmund in 2008.
Klopp took over Liverpool during one of the worst spells in their history and transformed them into Champions League winners in just four years.
He is also set to guide them to their first Premier League title.
Klopp's success during his time as a manager can partly be attributed to his ability in the transfer market.
Klopp has had a knack of getting bargains in the market and, when he's spent big, those transfers have nearly always paid off.
We've taken a look at his transfers across his time at Dortmund and Liverpool and ranked the 13 best that he's made.
13. Joel Matip
Transfer: Schalke to Liverpool | 2016 | Free
Klopp has previously said that Matip is the best signing he's made during his career.
He hasn't always been first-choice and he's suffered his fair share of injuries, but getting a quality defender on a free transfer was a great piece of business.
12. Lukasz Piszczek
Transfer: Hertha BSC to Dortmund | 2010 | Free
Another player Klopp managed to sign on a free transfer.
Piszczek has been a reliable full-back for Dortmund ever since making the move in 2010. Now 34, he's still going strong in his 10th season at the club.
11. Ilkay Gündogan
Transfer: FC Nuremberg to Dortmund | 2011 | £4.95m
Gundogan was a big part of Dortmund's success in the early 2000s, which saw them win the Bundesliga in 2012 and make the Champions League final a year later.
A reliable midfielder, Dortmund made a tidy profit on him when he signed for Man City in a £20m deal in 2016.
10. Shinji Kagawa
Transfer: Cerezo Osaka to Dortmund | 2010 | Free
Klopp actually signed Kagawa twice for Dortmund. This entry covers the first time he was signed: on a free transfer in 2012.
Kagawa played a pivotal role as Dortmund won back-to-back Bundesliga titles in 2010 and 2011.
He scored 29 times in 71 games before moving to Man United in 2012.
9. Andrew Robertson
Transfer: Hull to Liverpool | 2017 | £8.10m
In modern day terms, getting Robertson for just £8 million is a bargain.
The Scottish defender came into his own after a slow start at Anfield.
He's made 119 appearances in the last three seasons and is now arguably the best left-back in the world.
8. Marco Reus
Transfer: Gladbach to Dortmund | 2012 | £15.39m
Reus would have been higher up this list had he not been plagued with injuries over the past decade.
Still, he's been a great servant to Dortmund and is one of the world's best wingers when fully fit.
Since signing in 2012, he's played 266 times for Der BvB and scored 129 times.
7. Pierre-Emerick Aubameyang
Transfer: Saint-Etienne to Dortmund | 2013 | £11.70m
Aubameyang did exactly what he was signed for. He scored a bucket load of goals.
He managed to hit the back of the net 141 times in 213 games across four-and-a-half seasons for Dortmund.
The German club made a huge profit on him when he was sold to Arsenal in 2018 for £56m.
6. Alisson Becker
Transfer: Roma to Liverpool | 2018 | £56.25m
Liverpool surprised a lot of people when they paid made Alisson the most expensive goalkeeper in the world in 2018.
Many thought they had overspent for him. His critics were very wrong.
The Brazilian has provided a calming influence at the back and has helped Liverpool go to the next level.
5. Sadio Mane
Transfer: Southampton to Liverpool | 2016 | £37.08m
One of Klopp's first signings at Liverpool was Mane. It proved to be a masterstroke.
Mane has scored 77 goals in 161 games and has formed an incredible partnership with Mo Salah and Roberto Firmino in attack.
4. Mohamed Salah
Transfer: Roma to Liverpool | 2017 | £37.80m
Salah wasn't actually Klopp's first-choice target. He actually wanted Julian Brandt but, when he couldn't get the German, he settled for Salah.
That proved to be a huge slice of fortune for Liverpool.
Salah has excelled for the Reds. He shattered record-after-record in his first campaign with the club when he scored 32 Premier League goals as a winger.
He hasn't managed to hit those heights in the past few seasons but 91 goals in 144 games for the club is still superb.
3. Mats Hummels
Transfer: Bayern Munich to Dortmund | 2009 | £3.78m
Hummels was a major part of Dortmund's success under Klopp.
In his first spell at the club he was there for eight seasons and 309 appearances.
To get him for under £4m was magnificent business.
2. Robert Lewandowski
Transfer: Lech Poznan to Dortmund | 2010 | £4.28m
Lewandowski was famously travelling to Blackburn to discuss a potential transfer in 2010, but a volcano erupted in Iceland at the time and the ash cloud prevented him going to England.
The Polish striker ended up signing for Dortmund instead for just over £4m.
After a poor first season where he scored just nine goals, Lewandowski established himself as one of the best strikers in the world by scoring 94 goals in 144 games.
Unfortunately, they couldn't hold on to him and he moved to fierce rivals Bayern on a free transfer in 2014.
1. Virgil van Dijk
Transfer: Southampton to Liverpool | 2018 | £76.19m
Liverpool made a huge move when they made Van Dijk the world's most expensive defender in 2018.
He completely transformed Liverpool's defence. It was a liability when he signed, but he quickly made it into a strength.
Van Dijk has now established himself as the best defender in the world and he narrowly missed out on the Ballon d'Or title in December.
Klopp's decision to pay £76m for him was a huge gamble. But it's a decision that has paid off massively.
- On this day in 2015, Gerrard's last Liverpool game ended in a 6-1 loss to Stoke
- Curtis Woodhouse argues that Steven Gerrard was better than Paul Scholes
- Highlights of Gerrard's performance vs Germany in 2001