Apart from their unexpected defeat to Swansea City on 21 February, the Red Devils have been in fine form of late, recording six wins in their last eight fixtures in all competitions.
Although they are fourth in the Premier League, they have absolutely no chance of winning the English title as they are currently 10 points behind leaders Chelsea, who have a game in hand.
Due to this reason, United's only chance to secure a piece of silverware this season is the FA Cup.
However, Manchester United boss Louis van Gaal recently stated that his main priority this season is to help his side get a top four finish in the Premier League rather than win the FA Cup.
Still the Dutchman claims that United's clash against Arsenal on Monday is important for both the sides, not only in the FA Cup, but also in the Premier League "rat race."
"Arsenal and United are now in third and fourth place, so it is a big event with two good teams. I hope we can give a fantastic match for the fans," said the Dutchman, according to ESPN.
"I think if we beat them it is a big blow for them, but if they beat us it is a big blow for us. It is very important game, not only for the FA Cup but also for the (Premier League) rat race."
Meanwhile, Arsenal will also be hoping to beat Manchester United and progress to the semi-final of the FA Cup.
The Gunners, apart from their defeat to AS Monaco in the first leg round of 16 of the Champions League, have also been in fine form of late, recording five wins in their last six fixtures in all competitions.
However, their record at Old Trafford is not very great as they have failed to record a single victory at United's home ground in the last nine years.
Still Arsenal boss Arsene Wenger played down the importance of his side's record at Old Trafford, insisting that a victory or defeat all comes "down to quality."
"When the team is not as good, they lose," the manager Arsenal's official website. "It doesn't matter what shirt they wear, or what stadium they play in. It is down to quality."
"If I've learnt something in my life it's that the performance on the day decides the outcome of the day, not where you play."
The 65-year-old says he is certain that his side will be able to do well at Old Trafford on Monday due to the fact that they have won many games away from home this season.
"The fact that we can win away from home, that is important," he added. "If you haven't won away from home all season it's more difficult. But we know we can do well away from home.
"It's a big game, and every big win in a big game has an impact subconsciously in the belief of the team."
Manchester United: de Gea; Smalling, Evans, Rojo; Valencia, Herrera, Blind, Young; Rooney, di Maria; Falcao
Arsenal: Szczesny; Gibbs, Koscielny, Mertesacker, Bellerin; Cazorla, Coquelin, Ramsey; Ozil, Giroud, Sanchez
Where to Watch Live
The FA Cup game is set to begin at 7:45pm GMT (1:15am IST, 2:30pm ET) with live coverage in India on Star Sports 4. The match can also be watched via live streaming online on Starsports.com.
BBC One will be telecasting the game live in the UK, while viewers can also watch the match via live streaming online on BBC IPlayer. Audience in the UK can also listen to the match live on BBC Radio 5.
Catch all the FA Cup action in the US live on Fox Sports 1 or via live stream on FoxSoccer2Go. Audience in Canada can catch the game live on Sportsnet or Watch Sportsnet. Australia viewers can watch the match live on ESPN 2 or Watch ESPN.