Leonard was backed up by 20 points from Norman Powell as the playoff-bound Raptors won 111-98 to sit 2.5 games behind Eastern Conference leaders the Milwaukee Bucks.
LeBron James led all scorers with 29 points but his Lakers are languishing 7.5 games back from the final play-off place in the Western Conference.
Wesley Matthews scored with less than two seconds remaining to earn the Indiana Pacers, third in the East, a 108-106 win over the Oklahoma City Thunder.
OKC's Russell Westbrook had a triple-double but missed a last-second three-point attempt for the game.
Kyrie Irving had 31 points, 10 rebounds and 12 assists as the Boston Celtics beat the Sacramento Kings 126-120 to lie fifth in the East.
The Denver Nuggets are only one game off the Western Conference summit after a dramatic 100-99 win over the Dallas Mavericks.
Luka Doncic's dunk with six seconds remaining looked to have given Dallas victory, but having been fouled in the act of shooting he missed the resulting free throw.
It was to prove crucial as Denver's Nikola Jokic hit a fadeaway basket as time expired to snatch the win.
The Utah Jazz edged ahead of the San Antonio Spurs for the sixth seed with a comfortable 120-100 win over the Minnesota Timberwolves while the Orlando Magic beat the Cleveland Cavaliers 120-91.