Ruud van Nistelrooy revealed he made key tactical adjustments at half-time to spark 2-0 win over PAOK.
The Red Devils were lacklustre in the first half but , their first in European competition in 380 days.
Van Nistelrooy explained that he focused on improving the team's positioning during the break, saying: "We left positions too much in the first half, that's why we didn't get going, we couldn't find our 6s and play forward to the players we wanted in dangerous positions, like and Amad."
He added: "I think we did very well in the second half to stay in those positions and then you saw some fluidity occurring and better play on the ball and that led to more chances."
Van Nistelrooy will take charge of United for the final time against on Sunday before takes over as head coach on Monday.
The Dutchman has spoken out about his and Amorim's managerial focus, explaining: "I think that Ruben, what he's saying, he focuses on Braga and I focus on Leicester and that's a great one for now," and adding, "It shows we are focused on the day by day job and getting the maximum out of the team. So let him focus on Braga, I will focus on Leicester and let's see after that."
He also emphasised his dedication to his current role: "I am only busy with one thing on my mind. I want my last game as an interim, I want to prepare it as good as I can and give the players everything they need to get the best performance out of them and hopefully get three very important games, keep them at Old Trafford, that's my absolute focus."
Van Nistelrooy concluded with: "Other than that, I don't really look too far ahead, to be honest. It's too important."
You may also like
'Congress is now parasitic party surviving on crutches': PM Modi slams Congress at Nashik rally ahead of Maharashtra polls
In first video message after leaving jail, Kejriwal sounds poll bugle in Delhi
Ange Postecoglou confirms significant injury for Tottenham star - 'Very disappointed'
One in 10 admit they haven't cleaned some areas of their home in more than a year - here's why
This is the first thing one in three Brits do when they get home from work