We host the Merseysiders at 16:00 BST on Sunday and the mood could be very different going into the first international break of the season, depending on the result.
Liverpool have won both of their first two league fixtures under new manager Arne Slot, beating Ipswich Town 2-0 at Portman Road, before seeing off Brentford by the same scoreline at Anfield last weekend.
United are playing catch-up, following the late reverse at Brighton on the south coast.
“For both of us, it’s a huge game so early in the season,” Mainoo said in our exclusive interview for United Review, the official matchday programme.