While Harry Maguire started for Leicester and Jamie Vardy came off the bench, Mourinho opted against starting Romelu Lukaku and used a number of unusual starters including Luke Shaw, Matteo Darmian, Andreas Pereira, and Victor Lindelof.
"A match where I needed six changes, not three".
Mourinho had plenty of praise for Pogba, who is not yet at full fitness following France's World Cup win.
Leicester made a poor start, conceding an early penalty as Paul Pogba converted after three minutes, though Puel's side responded well and enjoyed strong spells of possession.
Following a tough couple of seasons under Jose Mourinho, when having his performances publicly criticised by his manager, the seven-cap England worldwide acknowledges that he can not afford to get too carried away.
While it may have been surprising to see Manchester United sign just one first-team player this summer, it was also surprising to see them keep hold of one player in particular - Anthony Martial.
"I didn't have any pre-season games". "We will have the same players, the injured players are not going to be back", said Mourinho. "I need more changes".
But according to the Telegraph's Sam Wallace, Mourinho was taken by surprise at Pogba's suggestion that all was not well between the pair, and believes they have a good relationship at Old Trafford.
"There are ways to improve your team: one way is to spend a lot of money and to bring in lots of important players, another way is to work and that's the way we have to do it", he added.
Vardy almost made a vital contribution as provider when he outmuscled Shaw and picked out Gray in the middle who was denied by another fine save by De Gea. So it was not easy to manage the game by the touchline point of view. "For us, it will be a hard season because I had my plans for many months".
Reflecting on his first United strike, Shaw admitted he hit a career high under the lights at Old Trafford and is desperate to repeat the feeling over and over again.