There is no doubt Liverpool are doing great this season, but my trust and hope for them died last season, afterwhich they have had a good play for a long while, they just suddenly start losing form for no reason, and that wasn't a good experience for them.
TBH, it is difficult to get your point. Which season you are talking about? This season or the last season? 
If you refer to this season, it is not over yet. We can't claim Liverpool does great season because it is just the beginning of the season. It is possible that there is a change in Liverpool performance for the next matches.
For clarity, I was talking about the previous season, and I'm shocked you didn't get what I was saying even when its clearly written there and you did underlining. However last season was a mess for them, from my perspective they should have lost their form especially when they were very close to wining the EPL title. This season they have been keeping a good record of clean sheet and all games won including the defeat of Manchester united with 3 null. From the look of things, its obvious to say that their new coach is doing a great job and if the result keeps coming in, they might likely win the EPL this season.
Manchester United lack both quality strikers and defenders as they have conceded 5 goals and scored only 2. But I don't think that's still the problem, because they have players who can perform well in those positions, it's just a matter of tactics that don't work, at the very least tactics that don't work, at the most - wrong formation of players and their personal instructions.
The problem can be both from the quality of the players and the tactics/strategy applied by the coach. However, the coach (Ten Hag) should be responsible with the problem on Man United. Ten Hag is the person who decided the formation, starting line-up, tactics, and even building the squad. Sure, he also gives the instruction and influences the mentality of the players. However, for some cases like Maguire and Antony, we also can't deny that it is also a problem of player's quality.I always tell my friends that, I don't like ten hag's choice of players. He should be more interested in players who can have the job done now, rather than making selections based on future potentials. Dont get me wrong, its nice ro have future potentials on your team with long durable contracts but when the current faith of the clubs success depends on skillful experienced players then, you have to go for it to keep the club in a good form.