NBA: Kawhi Leonard scores 25 points as the San Antonio Spurs top the Cleveland Cavaliers 103-74 on Monday night.

Cleveland forward LeBron James (23) shoots against San Antonio forward Kawhi Leonard during the first half of Monday’s game in San Antonio.

SAN ANTONIO — Kawhi Leonard scored 25 points and the San Antonio Spurs dismantled the ailing Cleveland Cavaliers 103-74 on Monday night in a showdown that turned into a major letdown for the defending NBA champions.

LaMarcus Aldridge and Pau Gasol added 14 points apiece for the Spurs, who won their fifth straight.

Cleveland (47-26) dropped its second in a row, set a season low for points and fell a half-game behind Boston (48-26) for the top seed in the Eastern Conference playoffs.

Cavaliers star LeBron James was injured late in the third quarter after taking an elbow to the base of his neck. He remained on the bench for a while receiving medical attention, then headed toward the locker room and didn’t return to the game.

James finished with 17 points, eight rebounds and eight assists in 29 minutes. Kyle Korver (foot) and Iman Shumpert (knee) sat out with injuries for Cleveland.

San Antonio (57-16) is two games behind Golden State for the league’s best record entering a home showdown with the Warriors on Wednesday. Darren Abate / The Associated Press the first losing season for the Mavericks (31-42) since 1999-2000, the season that owner Mark Cuban bought the team with Dirk Nowitzki in his second year.

The Thunder (42-31) won for the seventh time in nine games since a fourgame losing streak that matched a season high.