[10] They then travelled to Norway to play an additional friendly against Kristiansund BK, the hometown club of Norwegian manager Ole Gunnar Solskjær, winning it 1–0 through an injury-time penalty by Juan Mata.

[11] Their final game in the International Champions Cup and final pre-season game saw them play against Milan in Cardiff on 3 August, winning 5–4 in a penalty shoot-out after the match ended in a 2–2 draw, with goals from Rashford and Jesse Lingard; Wales international Daniel James scored the winning penalty.

[12] As a result of the COVID-19 pandemic in the United Kingdom, Premier League football was suspended on 13 March 2020; following the announcement in early June that the league would be resuming in mid-June, United first played an intra-squad friendly match at Old Trafford,[13] before arranging another friendly against Stoke City for 9 June; however, this match was cancelled after Stoke manager Michael O'Neill tested positive for COVID-19.

[17] United were held to a 1–1 draw by Wolverhampton Wanderers in their next game; Martial opened the scoring with his 50th goal for the club before Rúben Neves equalised with a long-range strike, only for Paul Pogba to miss from the penalty spot midway through the second half.

After Jordan Ayew put the Eagles 1–0 up against the run of play with just over half an hour gone, it took until the final minute of normal time for Daniel James to find the equaliser; however, Patrick van Aanholt's injury-time strike gave Palace their first league win over United since May 1991 and their first league win at Old Trafford since December 1989.

[19] James continued his goalscoring form in United's final game before the international break away to Southampton, opening the scoring after 10 minutes.

Jannik Vestergaard equalised for the home side just before the hour mark, but although Kevin Danso was sent off with 17 minutes to go, United were unable to make their numerical advantage count and the match finished as a 1–1 draw.

Marcus Rashford scored the only goal of the game from the penalty spot to give United their first win since the opening day of the season.

Marcus Rashford opened the scoring after a VAR check, as Victor Lindelöf was ruled not to have fouled Divock Origi.

The VAR was used again to check a goal scored by Sadio Mané, which appeared to have come off his arm, and was eventually ruled out for handball.

Liverpool did manage to find an equaliser through substitute Adam Lallana in the 85th minute to secure a vital point for both teams.

[25] On 27 October 2019, Scott McTominay netted United's recordbreaking 2,000th Premier League goal in a 3–1 victory against Norwich City at Carrow Road.

[26] Rashford had a penalty saved by Tim Krul a few minutes later, but scored on United's next attack to put them 2–0 up with less than half an hour played.

United were awarded a second penalty for a handball by Todd Cantwell, but despite a change of taker, Krul was able to make another save from Martial.

[43] After the newly introduced winter break, United got full 3 points at Chelsea, extending their undefeated run against the West London club to six matches.

[51] The return of the league on 19 June saw United draw 1–1 at Tottenham Hotspur; Fernandes equalised with a penalty kick after Steven Bergwijn's opening goal.

[64] The Fourth Round draw took place on 5 January, with United – were they to beat Wolves in their replay – drawn away to either Watford or Tranmere Rovers.

[66] Playing at Prenton Park against Tranmere, who had eliminated Watford just three days prior, United won 6–0; Harry Maguire and Diogo Dalot both scored their first goals for the club.

They suffered their first defeat to the West London club since the 2018 FA Cup Final, as well as ending their 19-game unbeaten run in all competitions.

It was only the second time they had met in a competitive, first-team match; their only other meeting was in the third round of the 1985–86 FA Cup, when Manchester United won 2–0.

Astana were United's – and any English club's – first ever Kazakhstani opponents, and it would also be the first time they had played against AZ; their only previous meeting with Partizan came in the semi-finals of the 1965–66 European Cup, losing 2–0 in Belgrade before a 1–0 win at Old Trafford a week later.

[81] United began their Europa League campaign with a 1–0 win over Astana at Old Trafford on 19 September; Mason Greenwood scored the only goal of the game, the first of his professional career, cutting inside off the right wing to shoot through the legs of goalkeeper Nenad Erić and become Manchester United's youngest goalscorer in European football.

The 3–0 win meant United could no longer be caught by third-placed Partizan in the group standings, confirming their qualification for the knockout phase.

[93] Due to the COVID-19 pandemic, the second leg was played nearly five months later, on 5 August; United went 1–0 down early in the second half, but Jesse Lingard equalised shortly afterwards, before Anthony Martial secured a 2–1 win with three minutes left.

[94] As a further result of the pandemic, the quarter-finals, semi-finals and final of the competition were moved to four venues in the German state of North Rhine-Westphalia, with all matches to be played behind closed doors.