A "satisfied" Louis van Gaal said Man United learned the controversial set piece routine they used in Monday's 3-0 FA Cup win over Shrewsbury Town from their Europa League opponents last week.
Van Gaal's position has been under severe scrutiny, with United having suffered back-to-back surprise defeats -- against Sunderland and FC Midtjylland -- before the win on Monday night.
There were fresh injury concerns though, with Cameron Borthwick-Jackson suffering an unspecified injury, and Will Keane sustaining a groin problem.
In terms of performance, it was a far more stress-free night. Facing a League One team, United crushed to a win, as Chris Smalling, Juan Mata and Jesse Lingard scored the goals. The result has secured a Cup quarterfinal against West Ham United in the next round.
"I'm satisfied," Van Gaal told BT Sport. "Also, before the match, I felt that. It's a matter of my profession."
There was a moment of controversy when United went 2-0 up. Juan Mata scored directly from a free kick when three of his United teammates obscured the view of the Shrewsbury goalkeeper while in an offside position.
The United manager said that his team had learned that trick from Midtjylland.
"We had seen them doing that," he explained. "We think it is always offside. So we asked the refs, from Portugal. They said, 'No, it's not, you can do that.'
"So that's what we have learned from Midtjylland. And today we scored. That's good."
The ease of the evening meant that Van Gaal could hand experience to younger, inexperienced players, with Joe Riley making his debut, coming on at half-time.
Injury-hit Keane came on in the 70th minute and promptly sustained another problem, as he suffered his fresh injury.
"It's unbelievable," Van Gaal said. "Also, Cameron Borthwick-Jackson, I changed at half-time, because of injury.
"I changed Juan Mata to give him a rest and also Anthony Martial. Then the sub also gets injured. But it's also the programme, I think."
Shrewsbury manager Micky Mellon insisted he had not seen the controversial second goal, which came in first-half stoppage time and left his side with a mountain to climb.
"First and foremost the quality of Manchester United was fantastic," he said. "I couldn't have asked any more of the players.
"I haven't seen any of the goals back. But we've got to come away and say we've had a fantastic cup run. We gave it everything. The players can hold their heads high."