#1 A high defensive line and necessary tactical fouls
Again, a big difference we are seeing in United's playing style is their high line. As previously mentioned, both fullbacks were essentially in the opposition box wherever possible in possession, allowing centre-back pairing Victor Lindelof and Axel Tuanzebe to lead a high line.
Whenever Inter got past the United press, Lindelof and Tuanzebe often committed cynical but clever fouls which allowed their teammates an opportunity to regain shape and form out of possession. This meant there was minimal space, if at all, for Inter to work with and naturally they struggled to get their attackers into the game.
Solskjaer doesn't want to allow opposition to dictate play, instead wanting his team to never let them off the hook. So far, players have done so brilliantly and their individual displays have been fairly impressive too.