Brendan Rodgers's side exceeded expectations last season by narrowly missing out on the Premier League title as United finished seventh under David Moyes - their worst league showing since 1989-90.
Liverpool also claimed the league double over their rivals - with a 1-0 win at Anfield and a 3-0 reverse at Old Trafford and Fletcher is keen to go some way to right those wrongs in Miami on Monday.
"It's Manchester United v Liverpool," he told reporters. "I know it's only pre-season and it's just a summer competition, but when United play Liverpool, it's always a big deal.
"We want to win every match, and it's no different when we play Liverpool. We have just beaten Real Madrid, the European champions, and we now want to go on and beat Liverpool.
"That is the sort of thing that gives the squad confidence. We have a lot of young players out here and you have to remember that. But all of us have to do it as a team, collectively, and we are doing that.”
United are without European football this season for the first time in 25 years and Fletcher feels the less-congested fixture list can aid the squad's title bid in the same way Liverpool benefited in 2013-14.
"We go out to win the league," he continued. "It is a dangerous mindset to have, to target fourth place. We are not players or a club that thinks like that and we will be going out to win the league.
"Liverpool didn’t have European football last year and they went close to winning the league, so hopefully we can go one better next year."