The opening is in some ways a mirror of the opening in the second courante, where a slowly ascending, mostly linear figure coupled F4 to F5. Here a fully linear descent from D5 to F4 occupies the first three measures, but the larger figure is an initial ascent from the opening D5 to the first Urlinie tone, F5, in measure 4 -- marked in the score.
In the final measures, ^3, as F4, is clearly heard again in the typical internal cadence to the opposite mode (at "x"), then an insistently rising pattern starting at "y" leads upward through the octave, but—as in the opening—the larger figure goes the opposite direction as the Urlinie descends in an unequivocal way from ^2 to ^1 in the final two bars. The point of interest is "what might have been" -- at "z" natural ^7 gives way directly to ^#7 over the just established V harmony.
The notation here is from Steve Wiberg's edition, available on IMSLP: link.
