Prior to the match, Arsene Wenger, who will soon be leaving, had asked for a peaceful match in his last visit to Old Trafford as the Arsenal manager. Besides that, fans are more concerned about the multiple arguments Wenger has had with Jose Mourinho over the many seasons.
After it was revealed that the French manager will be stepping down at the end of this season, Mourinho expressed his respect for Wenger and had asked for the Red Devils fans to respect him too.
Going into the match, the Gunners were in a disadvantageous position after their Europa League semi-final home clash against Atletico Madrid and risk losing out on the finals held in Lyon.
Meanwhile, Mourinho's team had an extended period of rest after their victory over Tottenham last weekend. Wenger had brought a young squad to Old Trafford, including youngsters such as Reiss Nelson, Joe Willock, and Eddie Nketiah.
Despite conceding the first goal, Arsenal's youth team showed resilience and the skills that they have. As compared to the senior squad, the youngsters seemed more willing to try things out, take more risks and have a number of great chances to score too.
Former Manchester United player, Mkhitaryan equalized for Arsenal in the 50th minute as he slotted one past David de Gea. Unfortunately, Wenger's team still ended off not having any points away from home in 2018 after Fellaini scored and the game sums up this season perfectly.
David Ospina: 7
The Colombian was unfortunate to concede the opener. He was well positioned to save Sanchez's header but the ball bounced away from his reach. The goalkeeper was kept busy with numerous set-pieces from the Red Devils but he dealt with them well until the final free-kick where Fellaini scored the winning goal.
Hector Bellerin: 7.5
In the midst of Paul Pogba's opener, Bellerin attempted to clear Alexis Sanchez's header. Unfortunately, his clearance hit the goalpost and went beyond Ospina's hands and the ball landed in front of Pogba.
Besides that, he was brilliant with his passing and crossing. Since the tie against Atletico Madrid, the right-back showed an improvement in his crosses delivered into the penalty box. In this huge match, his standard remained the same.
Calum Chambers: 7
Chambers partnered Mavropanos for the first time in Premier League and he had a pretty decent game. The English international made a few crucial blocks and interceptions in the match to deny Manchester United from extending their lead. He hardly placed a foot wrong and the young centre-backs indeed had a good game.
Konstantinos Mavropanos: 7
The January signing was handed his first Premier League start of the season against Manchester United. Following reports of his good display with the youth side, he showed that he can perform well on the big stage. The youngster was calm in his ball and alert of his surroundings.
Sead Kolasinac: 6
Kolasinac had little influence on the game and was busy defending on most occasions. He lost the ball far too easily with his inaccurate crosses throughout the match. In his rare Premier League start, it was unlucky that the former Schalke man suffered an injury and had to be replaced by Nacho Monreal.
Granit Xhaka: 7.5
The Swiss international was poor in the beginning stages of the match and earnt himself a booking. After receiving a yellow, Xhaka controlled his performance and was less rash in his tackles. In the match, the midfielder showcased his leadership qualities as he created plenty of chances for the youngsters to shine.
Ainsley Maitland-Niles: 7
Maitland-Niles displayed his keenness in helping his team move forward in attack. He laid quite a few good passes for Mkhitaryan and was eager to regain possession for his team. It was an encouraging performance from the youngster. He was fast and dared to challenge his opponents head-on.
Henrikh Mkhitaryan: 7.5
In his first visit back to Old Trafford, Mkhitaryan had a great first-half. He had chances to score and create, truly returning to his form while he played at Dortmund. After recovering from an injury, he scored on his return and it was an encouraging display from the Armenian international.
Alex Iwobi: 6.5
Iwobi enjoyed a far less satisfying first half during the match. He was poor in his turns and could not find his team-mate. Fortunately, his performance improved after the break and was more engaged in the play. He did not look extremely sharp but nonetheless, he did his best.
Reiss Nelson: 7.5
Nelson made his first premier league start away from home. In the build-up to United's opener, the Arsenal youngster was fouled but the referee, Kevin Friend, failed to blow his whistle. The English international is improving bit by bit as chances given to him increases. He ran around the pitch and exerted pressure on some of the defenders from United.
Pierre-Emerick Aubameyang: 6.5
Aubameyang did not have as many chances as he would have wanted to. When balls were played to him, they were usually directed towards the wrong side of him, resulting in the Gabon international not having the ball.
However, it is encouraging that Aubameyang has been willing to drop deeper to defend and also get the ball when necessary. It seems like when he plays with other first-team players such as Mesut Ozil, Alexandre Lacazette, and Aaron Ramsey, they have better communication as a team.
Substitutes:
Nacho Monreal: 6.5
He replaced the injured Kolasinac in the position of a left-back. There was quite a deal of defending which had to be done towards the last ten minutes of the match when Manchester United seemed to have switched a level up in their attack. Monreal dealt with the pressure calmly but the team conceded the second goal in extra time.
Danny Welbeck: 6.5
Welbeck was unable to find the net against his old club. The English man was given some time to have a run before the second leg clash against Atletico Madrid in Spain, where he is expected to start alongside Alexandre Lacazette.
Joe Willock: 6
He showed a few glimpses of what he could do in a match. However, the men in red dominated the last few moments of the match and there was little Willock could do in the attack.