Erik ten Hag played Jadon Sancho in the No.10 role as he felt there was space in Leicester's midfield for Manchester United to exploit.
Sancho replaced Alejandro Garnacho at half-time with United fortuitously ahead by one goal after 45 minutes that Ten Hag branded "rubbish".
Marcus Rashford gave United a two-goal cushion in the 54th minute and Sancho made it 3-0 in the 61st to effectively kill a contest Leicester had dominated in the first half.
Also read: What Ten Hag told fans at full-time
Sancho has performed brightly in his three appearances off the bench, having scored the equaliser against Leeds at Old Trafford earlier this month, and his return against Nottingham Forest came in the No.10 position.
"Second half, we play like the principles and the rules of the game from us," Ten Hag said. "So we transferred the game plan and then you see we are dictating the game. And with Jadon on the pitch, there was a lot of space in the midfield area to bring him there to get players playing between the lines, get more dynamics, it worked really well, him and Bruno on that side.
"And I think with Wout up front we get better pressing. That's due to the fact we are more controlling, dominating, dictating the game, finishing the game and in the end, is a deserved win. But the meaning of the first goal is important."
United were indebted to David de Gea for two superb saves from Harvey Barnes and Kelechi Iheanacho before Rashford put them ahead in the 25th minute.
De Gea recorded his 180th clean sheet for United, placing him joint level with Peter Schmeichel in the club's history, and Ten Hag admitted the goalkeeper had to mop up the defenders' "mess".
"He's doing really well and I think he had many more games [where] he had a lot of clean sheets," Ten Hag added. "It's not only the 'keeper - because we are defending with 11 - but there are moments you need the 'keeper.
"He already had many moments this season where he was so important and he saves points. That's his job, he knows that and in the right moment, you have to do it.
"Today the team needed him, it was a mess and he did the job. He made brilliant saves."
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