The 22-year-old has signed a six-year contract, the PA news agency understands, after the Reds paid an initial fee of £64million.
His fee could rise as high as £85m, which would eclipse by £10m the sum they paid Southampton for centre-back Virgil van Dijk in January 2018, but for that to happen the Uruguay international will have to meet every condition – ranging from goalscoring targets to winning the Champions League – set out in the deal.
Liverpool expect the eventual cost to be at least £75m providing Nunez plays regularly.
And while that fee is high, the striker’s wages are believed to be in the region of £140,000-a-week which makes the deal more palatable considering they are offloading Sadio Mane, one of the club’s higher earners, to Bayern Munich and hope to recoup about £40m from the sale of the 30-year-old.
The club moved quickly to see off competition from one other Premier League club, believed to be Manchester United, after manager Jurgen Klopp identified the player as his number one summer target.
Klopp was impressed – sources say he “fell in love” with the player – by what he saw in the club’s analysis of Benfica ahead of their two-legged Champions League quarter-final in April, in which Nunez scored home and away.
New sporting director Julian Ward, using contacts in the Portuguese market established in a previous role as scout for the club, flew to Portugal last week to ensure the deal was finalised quickly.
Nunez’s signing is a departure from the multi-functional player Liverpool usually target but Klopp and his coaching staff are convinced they can evolve the team to play to his strengths.
His lack of English is also not a concern as both assistant manager Pep Lijnders and development coach Vitor Matos speak Portuguese, as do a number of the squad as Brazil internationals.
The way Colombian Luis Diaz, a January signing from Porto, not only settled but flourished in his first few months despite not speaking English, highlighted how comfortable Klopp is with bringing in players who do not speak a common language.
Nunez’s arrival also continues the evolution of the team’s forward line.
With Mane heading out this summer, Mohamed Salah at the moment currently only prepared to commit himself to the final year of his contract and Roberto Firmino, 31 in October, likely to play out his last 12 months the forward line needs an injection of new blood.
Diaz, 25, provided the initial shot, the addition of Fulham’s 19-year-old Fabio Carvalho has boosted that and Nunez will complete the mid-to-long-term regeneration. Liverpool still also have Diogo Jota, who is also only 25.