Ranked Quads

Normal 6x6 sudoku rules apply.

QUAD CLUES: Each digit in a circle must appear in the surrounding 2x2 area. (If a digit appears twice in the circle it must appear twice in the 2x2 area.)

RANKED QUADS: The 25 2x2 areas in the grid each contain a 4-digit number (read in normal reading order from top left to bottom right.) If all these 4-digit numbers are ranked from lowest to highest (with rank 1 being the lowest and rank 25 being the highest), the number in a circle also gives the rank of its surrounding 2x2 area. All the 4-digit numbers are different, so there are no tied ranks.