The teenager turned down United in favour of the Bundesliga club last summer and he has gone on to flourish.
Bellingham was dictating Championship matches for Birmingham City at 16 but there were doubts over whether he could perform at the highest level at such a tender age.
The midfielder attracted a lot of interest last summer but United and Dortmund led the race for his signature.
After a tour of United’s training ground complex at Carrington and a trip to Germany, Bellingham gambled on a move overseas.
And that shows he could have handled playing regular minutes in a United shirt this term.
If Solskjaer had guaranteed the ex-Birmingham star a starting spot then he may have a future world beaten within his ranks for many years to come.
Instead, the England international will continue to see his stock rise in the Bundesliga before a European powerhouse prepares an approach.
“Honestly, I’m knackered now!” Bellingham said after losing to City.
“They’re brilliant, I think they’re one of the best teams in the world if not the best.
“The way they move the ball and the way they go to regain the ball after they lose it is world class.
“You give De Bruyne that much time in the box then he’s going to score and you give him that much time around the box then he’s going to put a ball in that damages is and it did.”
Speaking last year about turning down United, Bellingham said: “Well, you know, Man United have a great squad but my decision had nothing to do with Man United.
“I was so focused and so happy with the interest from Dortmund that this became my first choice.
“For me, it was Borussia Dortmund and that’s it. When you find somewhere that’s the best place to be, you kind of ignore everything else, you know what I mean?”