Ole Gunnar Solskjaer was appointed as full-time boss at Old Trafford on Thursday, having originally returned to United in December as caretaker manager.
When Solskjaer was appointed in December, Manchester United were 11 points off top four but the Norwegian has guided United to just one point off top four and to the quarterfinals of the Champions League.
Manchester United legend Gary Neville has now revealed what the club must now do after appointing Solskjaer as permanent boss.
“I think defensively is the main [area] to look at,” Neville told Sky Sports.
“There’s been so many changes in the defence.
“I actually think the defence has done very well. It looks makeshift on paper but performs quite well. (Antonio) Valencia and (Ashley) Young have done brilliantly for a few years.
“(Luke) Shaw has started to perform well. (Victor) Lindelof has had a good season, (Chris) Smalling is doing well. ‘But you need a dominant presence, that’s the key thing. You look at a (new) centre back and a full back and then there are other areas they may look at as well.”
Neville added: “From Ole’s point of view he does need the right people around him now.
“That’s something I said a few months ago. He needs quality people around him to ensure United get ahead of the game in recruitment.
“Solskjaer is not going to be a success unless the club get the right people around him and then get the right players in… that’s absolutely essential.
“The amount of money Manchester United will need to spend is big. But the club haven’t fallen short in that over the last few years. I think they will spend the money.”
Meanwhile, Solskjaer has told Manchester United fans that he is determined to pay them back for the support they’ve shown him, his staff and the players over the last three months.
“I’ve always had it, but I’ve got to say the last few months have been absolutely crazy with the way they’ve taken to the players, to me and the coaching staff,” Solskjaer said.
“We’ve really appreciated that support and hopefully we can pay them back now.”