That's slightly above the previous mark of 720,227 set last year.
The tennis major also set a first week attendance record of 423,427, including a single-day high of 61,554 for the combined day and night sessions on the first Friday.
The U.S. Open has ended on a Monday instead of a Sunday in each of the past two years because of rain.
Rain forces postponement of Nadal-GonzalezSilva leaves exit door open
