Haaland was linked with a move to Old Trafford before his move from Red Bull Salzburg to Borussia Dortmund in January.
Sports Livestream ⚽ JOIN NOW for FREE
Instant access to the BT Sport, Sky Sports and Eurosport
And Ince believes his former club must improve their attacking options if they want to challenge for the Premier League title next term.
“If they want to close the gap on Manchester City and Liverpool then they need a world-class striker,” the ex-midfielder told Goal.
“They had the chance with Haaland, the young kid who went to Dortmund, that was sad really. He is a very, very good young player who can improve and you can’t let people like that slip through the net.
“That was disappointing that they couldn’t get him. They have got to have someone in who gets 20-25 goals a season.
“There are players who Ole [Gunnar Solskjaer] will still feel should not be there next year. There will be more players leaving and more coming in.
“I think you have to get the right balance. You can’t always go too young. You need a right balance of experience and youth and there is still a long way to go to match Manchester City and Liverpool.
“They are going in the right direction and the quicker they bring in those players then the quicker that is achieved.
“They need another midfield player for sure. We don’t know what happens with [Paul] Pogba if he stays or goes. That’s another saga that we will have to go through once the season finishes.
“They need two strikers, I know [Marcus] Rashford is coming back but he is only young. You can’t rely on him all the time.
“[Anthony] Martial, for me on his day, is brilliant but he doesn’t have enough of those days. Ighalo is the wrong end of 30. He has done well but you won’t pin your hat on him for the next four years.
“If you look at all the top teams, all the best teams have the best strikers. Their strikers have 20-25 goals in a bad season. Manchester United lost that in [Romelu] Lukaku. That’s got to be their main aim.”
