United did not manage to sign any centre-backs and Neville was particularly surprised at the failed Alderweireld deal.
"It will be a hard season for everybody", Mourinho said on Friday night.
"You have to keep it in mind, but you have to keep working to get better and better because I am still quite young".
World Cup victor Paul Pogba's third minute penalty and a late goal from Luke Shaw gave Manchester United a 2-1 win over Leicester City at Old Trafford in the opening game of the Premier League season on Friday.
Manchester United fans couldn't hide their delight with Luke Shaw's performance vs Leicester City after he netted his first senior goal.
"I'll always give my best to the fans and my teammates no matter what's going on", he wrote, along with #pogfeelings.
United were outstanding in the early stages and I think the Foxes were in shock at the way they came out of the blocks and took control of the game.
Spurs finished the transfer window having made no new signings, despite their pursuit of Aston Villa midfielder Jack Grealish.
"I think football is changing and probably football managers should be called head coaches".
The comments from the Portuguese and Pogba are sure to see contentment behind the scenes come under bigger focus, but Friday's win was a welcome boost at a time of apparent discontent.
The Premier League season kicks off on Friday with Manchester United playing Leicester at Old Trafford.
Is there a rift between Paul Pogba and Jose Mourinho?
"We didn't receive (any offer) for any player".
The Englishman had a fine game in the Premier League's first match of the season and played his part in the 2-1 win.
Jamie Vardy got Leicester's late reply at Old Trafford (Steven Paston/PA).
Leicester pushed for a reply and got one in injury time in rather weird fashion, with sub Jamie Vardy heading in from point-blank range after Ricardo Perreira's cross had come back off the post.
Matteo Darmian, hoping for a return to Italy before the end of the month, tested Schmeichel at the near post early into a second half that United started with bundles of possession but few clear-cut chances.
United would have allegedly deemed an offer of £100m as good value for money, with the France worldwide only being 25 years of age and having the potential to play a leading role in the centre of the defence for a decade.