E'Twaun Moore only played six games in April and May before Sunday's regular-season finale at San Antonio.
He averaged just 4.3 points in his first season with Phoenix.
All that didn't matter with much on the line.
Scoring 22 points, Moore knocked down a 3 with 2.2 seconds left to give the Suns a dramatic 123-121 win without Devin Booker and Chris Paul.
Torrey Craig capped the win by blocking rookie Devin Vassell's 3 at the buzzer. before 4,738 fans at AT&T Center.
Suns coach Monty Williams elected to rest his All-Star backcourt, Jae Crowder (ankle), Deandre Ayton (knee) and Cam Johnson (wrist) despite needing a win to stay in contention for the top seed in the Western Conference.