Jurgen Klopp hailed Thiago Alcantara as one of the few players in the world that can improve Liverpool after the Spaniard joined from Bayern Munich on Friday.
Widely regarded as one of the world's best midfielders, Thiago won seven Bundesliga titles in seven years at Bayern and was instrumental as they lifted the Champions League last month in his last game for the club.
However, with just one year left on his contract, it only cost Liverpool £20 million ($26 million) plus £5 million in add-ons to secure his signature.
The 29-year-old becomes Liverpool's first major signing for two years, in which time they have won the Champions League and a first English league title for 30 years.
"He is an absolutely exceptional player and you are right it is difficult to improve a team like us in the moment in a normal way," said Klopp.
"If we take 3-400 million maybe we could find some players but even then it is not easy. In this specific case it is a player who brings a different dimension in our game, that's true.
"Some skills which in general are pretty rare but they suit us pretty well. It says nothing about the other players it is only different and that is what I was really interested in."
Thiago said in an emotional open letter to Bayern fans on Friday that it was the lure of a new challenge that convinced him to leave after trophy hauls in Germany and at Barcelona, where he started his career.
"He was pretty excited about the opportunity as well so there was not a lot of convincing needed," added Klopp.
"That helps as well, that somebody really wants to be a part of the specific project is nice. All the things we agree together. That's a win-win situation and I'm really happy that we could do it."
Thiago is not the only high-profile player to have swapped the Bundesliga for the Premier League during the transfer window as most of Chelsea's £200 million spending spree went on bringing Timo Werner and Kai Havertz to England from RB Leipzig and Bayer Leverkusen respectively.
Both are expected to feature against Liverpool on Sunday in an early clash between two titles contenders as Klopp said he rated Werner, who was linked with a move to Anfield, and Havertz as the two outstanding young talents in Germany not already at Bayern or Borussia Dortmund.
"It's a really good league. Yes with one very dominant team, but the rest is really tactically good, lots of talents. The Premier League is the league with the most money, the most competitive league and they are interested in these type of players," added Klopp.
"I think Havertz and Werner especially from these young boys were the outstanding players. All the other young and outstanding players play at Borussia Dortmund. It is a good league for England to scout and as long as they can afford the transfer fees we will see these kind of transfers for sure."