The former Plymouth man is relishing testing himself against the Champions and said: "It's a really big game and a big occasion for everyone.
"We're at home at the end of the day, so we want to put on a performance for the QPR fans.
"We gave a good account of ourselves against Manchester City, albeit we came up short, so we're determined to go one better against United."
Rangers will want to improve on their home record where they could have beaten Aston Villa, Blackburn and West Brom but ended up with ultimately disappointing draws.
The striker is hoping Neil Warnock's men can get 40 points on the board as quickly as possible but to do that they must start winning more games on their own turf.
"We need to turn good performances into victories at home, starting Sunday," added Mackie. "We need to make sure we concentrate on our own performance and not worry too much about United.
"We know we'll need to be at our best but we're a confident bunch and I'm sure we'll give a good account of ourselves."
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