Although they are ranked 6th now, but with their mediocre and even disappointing performances, it will make fans or anyone else feel that they will not be able to maintain their current position. For me personally it's not just the standings, it's the pattern of play they show too. sometimes some people don't care about the standings, but if their play is promising it will make them satisfied. Logically, when their play is good and promising, then their ranking in the standings will follow as well as their performance. I'm sure you know what I mean.
We're too focus to see the bad performance by Manchester United, but we forget if other clubs' performance also unstable and that resulting the points are widely spread. It's not like in the last season where the gap between top and middle positions are really far, it's need many many match to overtake them.
What we need to highlight is Newcastle which currently behind Manchester United.