City were confirmed as champions after United’s defeat to Leicester on Tuesday left them 10 points clear with three games remaining.
While it has taken until the final games for the title race to be settled, in truth United were never really in it, and City never looked back once they claimed top spot after Christmas.
The strength in depth available to Pep Guardiola has no doubt helped in their charge to a third domestic title in four years, and Solskjaer conceded it was something United must strive towards if they are to catch their rivals next season.
Asked whether having 10 players of quality on the bench is the target, Solskjaer told BT Sport: “You know if you want to take up the challenge with them of course we need to strengthen our squad.
“Congratulations to them, they’ve had a fantastic season.
“Very pleased with my boys, because they’ve made it into the last 10 days of the season with a Man City team ahead of us that are lauded as the best in Europe, so we’ve done well.
“But we want to take the next step and it might be that we need a couple more to have a strong squad [for next season].”
United still look on course to finish second bar a big upset, as they need four points from their final three games to claim the runners-up spot.
Solskjaer effectively handed the points to Leicester as he made 10 changes from the side that beat Aston Villa at the weekend, with one eye on Thursday’s clash against Liverpool.
Academy youngster Anthony Elanga was handed his debut, while the likes of Amad and Donny van de Beek were given rare starts.
And while United competed with their opponents after Mason Greenwood’s goal cancelled out Luke Thomas’ opener, they were eventually outplayed as Caglar Soyuncu’s bullet header separated the sides.
It speaks volumes about the difference in levels between City and United currently, and Rio Ferdinand feels Solskjaer was within his right to call for new arrivals.
“I think it’s evident,” Ferdinand said. “You see the team, if you change the squad. Man City can do this.
“They’d come here today and be comfortable, wouldn’t look like a team out of sorts, being thrown together.
“Man United today had young kids playing, the two wide boys, very inexperienced. Man City change their team like this and they just look like the first XI.
“You don’t see a change because of the quality, the depth in their squad.
“Man United, to get to that level, I think Ole is perfectly right, they have to invest in the transfer market and I imagine they will.”