In the last 5 games at Old Trafford in which Man Utd have scored (so excludes the 5-0 game), they have scored before the 20th minute in the last 3.
MUFC 4-3 LFC (Jan24): McTominay (10th minute)
MUFC 2-1 LFC (Aug22): Sancho (16th minute)
MUFC 2-4 LFC (May21): Fernandes (11th minute)
MUFC 3-2 LFC (Jan21): Salah 18th minute [Greenwood (26th minute)]
MUFC 1-1 LFC (Oct19): Rashford (36th minute)
And looking at the opening 15 mins this season, we are poor and they are relatively strong
Recent performances and stats are saying that Uniteds best punch will be thrown in the opening stages. If it lands, we can still turn it around (also backed by performances and stats), but if we can get through the opening 20 minutes, then our chances improve given the intensity will drop a bit and we should be able to control the game as that energy from the opening 20 dissipates a bit