The Red Devils, managed by former Everton boss Roberto Martinez, won nine of their 10 games in qualifying and boast some of the world's most in-form attackers, such as Kevin De Bruyne, Eden Hazard and Dries Mertens.
Neymar, who will lead Brazil's line as they bid to win football's showpiece prize for the first time since 2002, has cited Belgium as dark horses, as well as highlighting the superb recent form of Premier League top-scorer Mohamed Salah, which could be the catalyst for Egypt to cause an upset.
"I think the best-known teams are the favourites, as always," he said.
"And for the surprise, I think Belgium has an excellent team and can be a surprise in this World Cup. Salah is a great player who can make a difference in the World Cup."
que Deus nos abençoe e nos proteja— Neymar Jr (@neymarjr) November 29, 2017
Good bless and protect us pic.twitter.com/kpPJ5pQ7a0
Neymar was an instrumental figure in his country's ill-fated attempt to win the World Cup on home soil in 2014 as they suffered a crushing 7-1 defeat to Germany in the semi-finals.
However, the PSG star believes he is a more experienced player now and is better positioned to spearhead an attempt to win a sixth World Cup for his country.
He added: "The difference is hard to explain, but I think I'm more experienced, more wise, more 'cascudo', as we say in Brazil.
"This is because I had many experiences, I participated in a World Cup where we lost and I think I'll be more prepared for the next one, because I know what is like to be in a World Cup, I can be better prepared.
"So the Neymar in 2018 is better than the Neymar in 2014."