Manchester United have not had a real test yet, what they have succeeded to do is just a two game good performance. This match against Liecester to me isn't a real test either because they are a bigger side. It is expeced they would win Liecester with ease although the league is full of surprises especially when it comes to playing against weaker teams.
Maybe you don't remember when Manchester United beat Liverpool in the previous game, whether it was called a lucky win or we could call it a victory with team quality. What you say is not true at all. Ten Hag had found his best strategy to defeat his opponents. If the 1-0 advantage can be maintained until the long whistle, Manchester United is back on track, which is a team that is full of hope with 3 wins in a row with the current match taking place. Manchester United was stirred up at the start of this season with a lot of rumors and poor performances but look how easy it is for them to turn things around.
With a winning streak no doubt Ten Hag has found the right strategy for the Mancesher United squad, also the players who are fielded are very appropriate to fill the team's weaknesses. Previously Leicester had been beaten by Southampton and Ten Hag should have found it easier to think of the right strategy, because Southampton couldn't score any goal against Manchester United also in the previous match. The interesting is later when Manchester United will play versus Arsenal, for now possibility they can take full points from Leicester with only a few minutes left to full time.