We've checked the Reds' Barclays Premier League record and discovered it was only the eighth time this has happened since the inception of the division in 1992.
If Robin van Persie's effort that crossed the line had counted, it would have been only the second time Sir Alex's side had netted five times in the opening half in the Premier League following the 6-1 romp against Arsenal in 2001.
How many of the seven matches could you recall?
Check out the answers in the black box. The Barnsley and Sheffield Wednesday matches in 1997 were consecutive league fixtures while the most recent match, the 5-1 against Fulham in 2006, is the quickest United have hit four goals in the Premier League - 19 minutes.
1. Sheff Wed H 5-0 16/3/94
2. Barnsley H 7-0 25/10/97
3. Sheff Wed H 6-1 1/11/97
4. Arsenal H 6-1 25/2/01*
5. Sunderland H 4-1 2/2/02
6. Newcastle A 6-2 12/4/03
7. Fulham H 5-1 20/8/06
* United scored five times in the opening half