The Foxes chief admits Louis van Gaal's side are starting to click after they kick-started their season last week.
A 4-0 Premier League win over QPR was their first victory of the season under Van Gaal after a troubled start which saw them lose to Swansea and suffer a 4-0 humiliation at MK Dons in the Capital One Cup.
But Pearson insisted United have begun their road to recovery ahead of their clash at the King Power Stadium on Sunday.
He said: "United look like they have a swagger back, they have added quality. Whenever there is a change in manager you can have people who have a short-term impact.
"When you have someone in charge for as long as Sir Alex (Ferguson) the transition period will never be easy.
"They have been a huge presence within the English game for a long time. I'm sure they will reignite that at some point."
Leicester have impressed on their return to the Premier League after a decade away, drawing at home to Everton and Arsenal before their opening win at Stoke last week.
They still earned plaudits in a narrow defeat at Chelsea and Pearson wants his side to maintain their momentum on Sunday.
He said: "If you look at the Arsenal game, there is no doubt there was a spirit and togetherness. We have some very exciting players and prospects.
"We can't be happy with what we've done so far. I don't know what system they (United) will play to start with."
Manchester United 4 QPR 0 player ratings
Manchester United 4 QPR 0 player ratings
1/22 David de Gea
Was found wanting in the first half after very nearly being caught out by Matty Phillips. Did well to save from Armand Traore in the second period, however. 7
Posed a considerable threat throughout the match down the right flank and broke effectively. A good outlet for United. 7
3/22 Marcos Rojo
Slotted into the Manchester United backline with ease. Looked decent with the ball at his feet and showed a willingness to get forward. 7
4/22 Tyler Blackett
Perhaps a misfit on a teamsheet of Galacticos, the young defender didn't look out of place in Louis van Gaal's side. 7
5/22 Jonny Evans
Needed to be alert to a QPR counter attack in the first half but had precious little to do. 7
6/22 Angel Di Maria
Showed the ambition and ability to really trouble a poor QPR side at Old Trafford. His goal had an element of luck about it but his quality is undeniable. A man of the match display. 9
7/22 Daley Blind
Cut a composed figure at the heart of Manchester United's midfield and showed the Red Devils supporters exactly what they've been missing of late. 8
8/22 Ander Herrera
Took his goal really well and linked Manchester United's defensive midfielders up with the more attacking players brilliantly. 8
9/22 Wayne Rooney
Seems more mature with the captain's armband on. The England man put in another decent shift and grabbed himself an impressive goal too. 7
10/22 Robin van Persie
While the Dutchman always poses a considerable threat, he looks out of sorts at the moment. 6
11/22 Bets of the bench: Radamel Falcao
Didn't have long to make his mark but showed enough drive to enthuse the Old Trafford regulars. 7
12/22 Rob Green
Any goalkeeper who concedes four goals isn't going to score too highly. Made a number of decent saves which keeps his score respectable. 5
13/22 Mauricio Isla
Was brought to the club to give QPR a threat down the flank but continues to struggle in English football. 5
14/22 Steven Caulker
While the former Cardiff City man didn't do a great deal wrong, he went missing for large periods. 5
15/22 Rio Ferdinand
Would have had dreams last night of scoring the winner against his old club but was easily overrun by the new United talent. 5
16/22 Clint Hill
Taken off at half-time, his deflection took Angel di Maria's cross into his own net. A poor afternoon. 5
17/22 Junior Hoilett
Made little impact on the game but shouldn't let it get him down. These aren't the games which count for Rangers. 5
18/22 Niko Kranjcar
Showed glimpses of class but, like many of his team-mates, he failed to make his mark. 5
Didn't look match-fit at times and subsequently delivered a lukewarm performance on his debut. 5
20/22 Leroy Fer
Returned to the Premier League with QPR after relegation with Norwich City. Did little to suggest he will avoid that fate again. 5
21/22 Charlie Austin
A dangerous player at QPR's disposal but was left isolated for large periods. 6
22/22 Matty Phillips
Was bitterly unlucky not to score in the first half after David de Gea's error but it wasn't to be. 6
He continued: "It will be interesting in itself. They have some very good players, there is no doubt about that. Can we play the game not the occasion?
"The scrutiny and build up to games like this would suggest there is an awful lot at stake. That in itself can bring different pressures.
"We have to get our preparation right and try and not get too wrapped up in the occasion."Reuse content