The Toffees opened the scoring when substitute Leighton Baines's corner eluded David De Gea and the ball bounced in off Victor Lindelof for an own goal.
Despite a VAR check on a possible foul by Dominic Calvert-Lewin on De Gea, it was allowed to stand.
Greenwood came off the bench to salvage a point with a well-struck equaliser after he had initially played the ball wide to Daniel James and received a return pass by the winger.
More to follow...
MATCH DETAILS
United: De Gea; Wan-Bissaka, Lindelof, Maguire (c), Shaw; McTominay, Fred; James (Mata 86), Lingard (Greenwood 65), Rashford; Martial.