The second-half substitute put United ahead before Bernardo Silva's equaliser took the tie to a penalty shootout, ultimately won by City.
"Not so much, but the approach from every player is individual, but also to see which players were available and had a full pre-season," Ten Hag explained. "Like Amad and Rashford. Both had a full pre-season, were available.
"It’s always a lot working in the wide areas, pressing, compact pressing but also behind in attacking. We expect a lot of movement in behind, so run speed. We need fresh players but also players to start.
"To bring Alejandro, always a very good sub, also that is in your back (pocket), so there were more reasons not to start with him but he did very well. He came in and the plan went as we thought it should go. It’s only disappointing we couldn’t bring it over the line."