Fred and Anthony Elanga helped extend Manchester United's strong record from substitutions against Leeds on Sunday.
Both players found the back of the net for United after Ralf Rangnick made a double change on the 67th minute.
Rangnick's decision to take off Paul Pogba for Fred caught some by surprise, but it immediately paid dividends when the Brazilian scored within moments of entering the pitch and the substitutions looked better again when Elanga made the game 4-2.