Durant shot a decent percentage, but the point is Durant didn't get his usual number of shots.
Leonard got right up on his body and stayed there most of the time. He hounded him all over the court, muscled and pounded him, and generally harassed him. He overplayed the lanes to prevent passes to Durant by his teammates.
In effect, he was denying Durant the ball or any space when he did touch it. And I seem to recall he didn't get but a couple of fouls while he was doing it which is unusual respect by the refs for a rookie up against a superstar.
Meanwhile he was picking up 15 pts of his own to offset Durant somewhat and rebounding inside like a fiend. Couple of times he kept the ball alive and another Spur picked it off.
And speaking of rookie vs. superstar, Leonard never backed down from the challenge.
Beautiful all around game, Rook!