Blackburn Rovers head coach Tony Mowbray revealed that he identified a major weakness in the Whites defence ahead of Saturday's 2-1 victory which paid dividends for his side.
Mowbray became only the second manager to hand Marcelo Bielsa's Whites side a Championship defeat at Ewood Park as Danny Graham and Darragh Lenihan headed home two corners to cancel out a Mateusz Klich leveller.
The 54-year-old though revealed afterwards that it was always part of his plans to attack United from set-pieces believing he found a major weakness in Bielsa's team if you could take away the aerial presence of "man mountain" Pontus Jansson and captain Liam Cooper.
"We'd had an international break to prepare," Mowbray explained. "It gives the staff a good chance to study the opposition when you've got two weeks to watch five or six full games, try to pick their weaknesses and strengths.
"You come up with gameplans and we had two days to put it together. I'm just so pleased for the players really. The set-plays today are something we worked really hard on.
"Pontus Jansson is a monster of a man and (Liam) Cooper is dominant but you take those two out of the box, we felt they were vulnerable, which is what happened.
"Whoever was getting marked by those two played wide; for the first goal Graham came powering through the middle and scored. For the second goal, Lenihan did the same.
"But we had to dig in. They're a great team, with wonderful footballers and a world-class coach who has got them playing attractive football. It doesn't mean you should succumb. You have to fight, stand up and be counted. We did that today."