The Red Devils slumped to their third loss in five games at the King Power Stadium on Saturday after a dramatic finish to proceedings.
United led 1-0 in an exciting clash thanks to Mason Greenwood’s superb early strike, only for Youri Tielemans to hit back brilliantly.
The game was then finely-poised heading into the last quarter of an hour, with substitute Marcus Rashford - making his eagerly-awaited return from shoulder surgery - equalising with eight minutes remaining after Caglar Soyuncu had edged Leicester ahead.
However, Jamie Vardy immediately restored the hosts’ advantage, with United’s misery complete in stoppage time as Foxes substitute Patson Daka bundled home.
Solskjaer’s side have not won any of their last three matches and now face a gruelling run of fixtures, with games against Liverpool, Tottenham and Manchester City coming up in the Premier League as well as two Champions League ties against Serie A outfit Atalanta.
And afterwards the Norwegian admitted that he probably made errors with United’s team selection, having brought back captain Harry Maguire earlier than expected following a calf injury.
There were also recalls to the starting XI for the likes of Paul Pogba, Cristiano Ronaldo and Jadon Sancho in the East Midlands, while Nemanja Matic also started with the likes of Fred, Anthony Martial and Edinson Cavani unavailable, with Victor Lindelof deputing alongside Maguire with Raphael Varane sidelined.
"The four goals we conceded were very poor," Solskjaer told Sky Sports.
"When you concede goals like that in the way we did, we don't deserve to continue that run. Definitely the performance was very below-par and not good enough. We got a very good goal with Mason and we were knocking on the door to get another one; sloppy play and we concede a goal.
"In the second half, it was end-to-end but they created more chances and conceding at set-pieces was disappointing. Conceding seconds after the equaliser shouldn't happen. I picked the team; Harry showed no reaction. I hold my hand up if it doesn't work out and sometimes it doesn't.
"When you concede four, I probably made a couple of bad decisions."
Pogba, meanwhile, lamented United’s poor habits and demanded changes moving forward as he questioned their lack of maturity.
When those comments were put to him in his post-match press conference, Solskjaer said: “We didn't deserve points today.
"We started well, Mason scores, shows his qualities and then for a little while you think maybe we can get the second, then we gift them the first goal.
"Maturity? I wouldn't say maturity. I would say the focus in key moments.
"You know, two set-piece goals, one goal 10 seconds after we've just equalised, that shouldn't happen, and of course the first goal we gift them that one.
"All of the goals were disappointing how we've conceded them."