The Red Devils legend has hailed the Brazil international for his performances at Anfield, especially this season.
Firmino has been an integral part of Liverpool’s success domestically and in Europe.
Mohamed Salah has stolen the headlines, but Jurgen Klopp has never underestimated the important role his frontman has played.
Liverpool rewarded the 26-year-old this weekend by handing him a new improved five-year contract.
And Neville says the goalscorer’s workrate is something the likes of United, Real Madrid and Barcelona would be envious of having in their frontlines.
When picking his Premier League team of the season, Neville told Sky Sports: “I love Sergio Aguero, and he’s been in my team every single year.
“He’s been my favourite striker in the past four or five years but I just felt that Firmino should be in.
“When I watch Liverpool, he’s been the catalyst in term of the pressing, the back-tackling, from the runs he makes in behind, he’s very unselfish.
“I think if you’re Pep Guardiola you’d want him as your striker in terms of the way Jesus plays and the runs forward but also the runs back.
“Jose Mourinho would want him at Manchester United, I think Real Madrid would want him, Barcelona would want him.
“He doesn’t get the credit that Salah has had this season, but for me, Firmino should be in.”
United hitman Romelu Lukaku has had a solid first year at Old Trafford, although his ankle injury suffered against Arsenal on Sunday may have ended his campaign, with Marcus Rashford poised to fill his shoes.
Meanwhile, Real are set to overhaul their attack this summer, and Barcelona will need a long-term replacement for 31-year-old ex-Liverpool striker Luis Suarez at some stage.