This graph show what a BS metric Expected Goals are. Previous weeks it would have been the reverse with the Nix up there with nothing to show for it like the Jest here.
Not really a BS metric. It basically just measures the likelihood that a shot from a given location, distance, angle, technique used, defender pressure etc etc, will result in a goal. If you pick a season and look at the season-long cumulative xG for the premier league (as an example), it pretty accurately shows who the best and worst teams are, and this lines up fairly accurately with league positions.
What you're talking about is variance.. there's a lot of variance and luck involved in a single football match. I thought we played well against the Jets but still think we were lucky to win and the Jets were a better side on the night. However, there have been matches this season where I've thought we were the best team and seriously unlucky to lose. Just the way football goes, I guess..
I am with Ninja on his interpretation of what the graph actually says (although the intuitive interpretations are much more fun). It really shows than before the Jets game started, if you put your money on Phoenix, you would likely have collected a nice payout.