The 21-year-old kept his nerve to sidefoot past Pepe Reina, after David De Gea had saved from Daniel Maldini, to ensure the Reds triumphed 5-4 on spot-kicks, following a 2-2 draw in Cardiff.
Speaking after the game at the Principality Stadium, the boss said the winger had been a welcome addition to his United squad during pre-season, after arriving from Swansea City in June.
“Dan is ready to go. He’s had a great pre-season and has fitted straight into the group, both as a player on the pitch and in the team, and as a person and a personality in the group,” Ole said in his post-match press conference.