The way I look at it, is the rolling 10 smoothes out the impact of individual results, so you're looking at a more consistent trend line.
In this chart, you're looking at almost 2 season's worth of matches (9 from two season's ago, last season, and 24 from this).
Each data point is a quarter of a season (10 of 38 matches).
City have consistently been better than us, other than a period just past halfway last season, & latterly.
Having said this, if the trend was smoothed out, we are in an uptrend, & City had perfection for awhile, dropped off but were stable, and latterly are in a significant downtrend.
Trends can change, City could find their mojo again, but looking at recent trends I'd say were in good shape to win this thing, and maybe City isn't as good as we think they are.