He played a CB in midfield to specifically go man-to-man with Pogba. Not only did it stifle Pogba and limit his impact in attacking areas, it also made him a liability. By not allowing him to get on the ball and make things happen, you're forcing him to be a more disciplined midfielder and effect the games in other ways, which he's not going to do. They targeted his defensive fragility tonight by having Draxler run off him and occupy the space he was supposed to be in; something that was evident in the first half and continued throughout the 90 minutes. I'd say rendering your opponent's best player useless and exploiting his weaknesses is a pretty good example of tactically outdoing someone. At the highest level, you have to be able to make adjustments and Solskjaer didn't. A potential solution would've been to move Pogba deeper because Marquinhos, who was superb, isn't going to be able to shadow him, which means you're able to get your best player on the ball, even if it is in deeper areas, and fill the space Draxler was exploiting all night all in one simple change.
You also had Alves, a right back, playing on the right wing and doubling up on our best wide player. Martial was struggling even before the injury because we weren't able to get him the ball with Kehrer isolated. Flip that around and look at their best wide player, Di Maria, and look at the amount of times they isolated him with Young. That was a clear part of their game plan from the word go; they obviously liked the Di Maria/Young matchup and wanted to exploit it because it was a problem, especially with Bernat's overlapping runs, even when Lingard was on, who's very good at fulfilling his defensive responsibilities. By bringing on Mata you're only exacerbating the problem. An alternative change would've been Dalot for Lingard in an attempt to counter Di Maria by utilising the same tactic Tuchel adopted to limit Martial.
You have to be able to acknowledge the game isn't going to take the same pattern when you lose Martial and Lingard and change what you're doing. They're a huge part of how we want to play and you can't replicate that with Mata and Sanchez but that's what he tried to do.
Tuchel is one of the very best tactically speaking, so if you're talking about OGS as a caretaker and not a potential permanent manager of one of the world's biggest clubs, there's no shame in being outdone by him. But he is being touted by some as our next manager so he should be judged against those standards, and imo, he's done very little to prove he belongs at this level, and I say that based on his overall time here, not just tonight. This club needs an elite manager.