Goals from John Stones and Fernandinho ensured Pep Guardiola’s side reached the final for the fourth consecutive year in a row, while defeat means Solskjaer has lost his last four semi-finals as United manager.
United gave as good as they got before Stones’ opener but the home side were on the ropes for a period after the defender’s goal, with the visitors threatening to score a second through Riyad Mahrez and Raheem Sterling.
Despite the tide turning in City’s favour, Solskjaer waited until 15 minutes from time before introducing Mason Greenwood for Scott McTominay.
However, it was the Norwegian’s bizarre decision to sub on Donn van de Beek in the 89th minute for Fred that really raised eyebrows.
The Dutchman has been starved of opportunities this term and has started just two Premier League matches for the Red Devils since his £40m arrival from Ajax.
However, Solskjaer insists that he felt the side he had on the pitch could reverse the result and that he didn’t want to make too many changes.
‘After they scored I felt we took five minutes to get back into the game, into the swing of things, but then we put some more pressure on them.
‘We started to build more momentum but just didn’t have that edge, that extra quality to get the goal.
‘So it was about who do you put Mason on for, because you know Mason can create something out of nothing.
‘But the feeling was that we did put them under some pressure, they did make subs as well, so it was a moment to wait for that one.’
Solskjaer is expected to ring the changes, meaning Marcus Rashford and Bruno Fernandes could get a much needed rest.
Daniel James, Axel Tuanzebe, Odion Ighalo, Juan Mata and Nemanja Matic are all likely to come into the side.