United made the move to sign the veteran striker on a free transfer after his contract with Paris Saint-Germain expired.
Initially, Cavani was used off the bench, but has seen his involvement continue to grow, with performances making it difficult to leave him out.
There has been much discussion about the Red Devils’ best option through the middle, after the United boss took a look at all of his options in the first half of the season.
The 33-year-old has two goals in his last four league games, but according to Neville, it is his work off the ball that has made him undroppable to Ole Gunnar Solskjaer.
“Yeah I was a little bit nervous,” Neville told Sky Sports about the signing. “Obviously the last minute nature of his arrival, reminiscent of signings that have gone wrong over the past few years for Manchester United. But I have to say he’s been a revelation.
“His attitude, which is the only real question about him because his quality is fantastic, is spot on. His out of possession work is far better than [Anthony] Martial, [Marcus] Rashford and [Mason] Greenwood.
“They’ve got a lot to learn those young players in terms of how he operates when Manchester United haven’t got the ball and I think ultimately, those young three I’ve named, haven’t grabbed that No.9 spot.
“He’s come in, off the bench to start with, then you see his movement when he’s started playing, they look more physical up front when he’s there and he’s done brilliantly for United in this last month or so.”