The 20-year-old right-back signed from Los Rojiblancos on Wednesday on an initial two-year loan deal, and the defender arrives to place some pressure on Glen Johnson ahead of the new season.
Manquillo began his youth career at Real Madrid before moving to their cross-city rivals back in 2007 and he eventually made his senior bow in November 2012.
The Spaniard was limited to just 14 appearances in total at Vicente Calderon, with Juanfran establishing himself as first choice for a side that became recognised for having one of the finest defences in Europe last season.
Speaking to Liverpool's official TV station, Manquillo has described how delighted he was when he learned of the Reds' interest and also talked up the side's heritage and reputation on a European scale.
He said: "First of all I'm happy to be here and very happy to have signed for a club like Liverpool. They are one of the biggest in Europe, any footballer would want to come and play here.
"When they tell you Liverpool want to sign you, I think like any player, you are absolutely amazed and you don't think about anything else other than going straight there.
"It is one of the biggest clubs in Europe and no other English team has won more European Cups. It has a superb history and I think it one of those teams nowadays, like I said before, that any player would want to be a part of.
"It was a great group of players but from a a personal point of view, it was a disappointing year for me with injuries. I was unlucky with injuries. We managed to achieve things that from the outside appeared almost impossible
"Let's hope that I find something similar here. A team that has the highest aspirations and wants to win as much as possible."
Manquillo becomes the Reds' seventh signing of the summer following the arrivals of Dejan Lovren, Adam Lallana, Lazar Markovic, Rickie Lambert and Emre Can, while Divock Origi will join next season once his loan stay at Lille is over.
The new defender could be involved when Brendan Rodger' side take on Borussia Dortmund on Sunday ahead of the Reds' opening game of the new Premier League season against Southampton on August 17.