There was a ton of action on the court at the U.S. Open men's final on Sunday ... but there was even more in the stands, 'cause Kendall Jenner couldn't keep her hands -- or lips -- off her NBA star boyfriend, Devin Booker!!
The couple has been inseparable recently -- they hit up the NBA 2K23 launch party in Los Angeles on Thursday, before jetting off to New York City for the weekend.
Jenner and Booker hit up a bunch of New York Fashion Week events throughout the weekend ... sitting front row in multiple flashy outfits.