There is very little to separate the side in the Premier League table at the moment as Arsenal sit a point ahead of United, but Louis van Gaal's side managed to grab all three points when they won 2-1 at the Emirates Stadium earlier on in the season.
The Spaniard told MUTV: "Now we are looking forward to our match in the FA Cup because it's a very big chance to win a trophy this season. But we have to respect Arsenal because they are playing very well.
“We are Manchester United and we are not afraid. We are going to play in front of our fans and we need them [for us] to win."
Arsenal have been coming into their typical late season form when they need to rally put some wins together to help get them into the Champions League places, so many people will see them as slight favourites to go through as they have managed to overtake United in the process.
But United have had the upper hand in this fixture of late, with Arsenal's last win coming in May 2011 thanks to an Aaron Ramsey strike.
Both side's will be keen to win this quarter-final match with it being their only realistic hope of winning silverware this season. The victor could also land a psychological blow with the two sides so close to each other in the league table, which could have a lasting effect between now and the end of the season.