SAN ANTONIO -- The last opponent any team wants to play when it's struggling is San Antonio, which has cool efficiency, constant defensive pressure and a deep bench that runs weaker teams ragged. Just ask LeBron James and his slumping Cleveland Cavaliers, who on Monday became the latest victim of the Spurs' juggernaut.

Kawhi Leonard scored 25 points before leaving to a standing ovation and chants of M-V-P with 10:32 to play as San Antonio Spurs waylaid the defending NBA champion Cavaliers 103-74 at the AT&T Center.

A game that was supposed to be one of the league's late-season marquee matchups was instead a dud, with the Spurs dominating after the midway point of the first quarter thanks to Leonard, 14 points from LaMarcus Aldridge and dynamite play from their reserves.

"We had a really good night defensively -- everything came from that," said Spurs coach Gregg Popovich, who refused to say if playing this well against one of the NBA's best teams was a measuring stick.

"We just play the games and in every one there's some good and some there's some bad," Popovich added. "We'll watch the film and go over what we think we could have done better. At this point of the season, you are what you are."

Cleveland's LeBron James suffered a blow to the back of his neck in the final minute of the third quarter after a collision under the basket with the Spurs' David Lee. He slumped to the floor near mid-court and stayed there for several minutes before walking to the bench on his own. With the Cavaliers trailing 81-58 entering the fourth quarter, James -- who scored 17 points on 7-of-17 shooting -- did not see the court again.

James twinged a little in pain when putting on his shirt after the game and said he would be fine and not miss any time on the court.

"San Antonio is a well-oiled machine and they exploit anything you are not doing well," James said. "At this point in the season, we just aren't playing good basketball. It's frustrating right now, but we are a veteran ball club and we will work through this and get things together. We've been like a rollercoaster all season long and we have to get things right."

Pau Gasol added 14 points and Manu Ginobili hit for 12 for San Antonio (57-16), which pulled back to within two games of idle Golden State in the race for the best record in the NBA and the Western Conference. The Spurs have won five games in a row.

The Spurs and Warriors play in San Antonio on Wednesday for the third and final time of the regular season; the Spurs have won the first two games between the teams.

Tristan Thompson added 11 points for the Cavaliers (47-26), who fell a half-game behind idle Boston for the best record in the Eastern Conference. Cleveland's 74 points were a season low.

The game had a playoff fervor from the opening tip, but that was soon derailed with the Spurs using a 17-8 run over the final half of the first quarter to assume a 28-18 lead after the initial 12 minutes of play. The Spurs' bench contributed mightily to the surge, outscoring Cleveland's reserves 15-0, with Ginobili scoring seven straight points, hitting a layup and Gasol pouring in a 3-pointer with 3.7 seconds to play.

"For sure we were very sharp tonight," Ginobili said. "Rotations, switches, everything went well. Offensively, we played well, too. It was a great combination against a team that motivates you. You want to play your best against them."

San Antonio coach Gregg Popovich drew his ninth technical foul of the season arguing a continuation foul call on Leonard on a 3-point play by James midway through the second period.

The Spurs led 42-32 at the 6:20 mark of the second quarter before Irving was stripped of the ball on two straight possessions that led to layups on the other end for Aldridge and Lee, respectively.

Cleveland went a stretch of two minutes in the middle of the period in which it had five turnovers in six possessions, and San Antonio took advantage to bump its lead to 64-40 at halftime.

Leonard had 15 points in the first half while Aldridge hit for 12 as San Antonio outshot the Cavaliers 54.3 percent to 39.5 percent and committed just one turnover in the first two quarters.

James led Cleveland with 12 points and Thompson added 10 but the Cavaliers' bench did not get a point out of the four reserves that saw the court in the first half.

If Cleveland was going to get back in this game, it needed to make something happen in the first six minutes of the third quarter. But even though the Spurs missed seven of its eight shots in the quarter, they actually expanded their lead to 25 points, at 68-43, by the 7:38 mark of the quarter.

The first points for a Cavaliers' bench player came with 2:59 to play in the third quarter on a layup by Channing Frye off a James assist. By that time, San Antonio's reserves had scored 30 points and the game, for all intents and purposes, was in the books.

"San Antonio just looked so much faster than we did -- we were trying to do to the right thing but they were always there ahead of us," Cleveland coach Tyronn Lue said. "We scored 74 points and shot 4 for 26 (on 3-pointers) so we didn't really give ourselves a chance. We are the champs and we are going to get everyone's best shot and we know that. Now we just have to see what we are made of."

NOTES: Monday's game was the last for Cleveland this season against a Western Conference opponent. ... The Cavaliers have already made a franchise single-season record 941 3-pointers in 2016-17. That is the third-most 3-point baskets made by any NBA team in a single season, trailing only Golden State in 2015-16 (1,077) and Houston this season (1,070 through Sunday). ... Against the Wizards on Saturday, Cleveland F LeBron James passed Maurice Cheeks (7,392) for 12th place on the NBA's career assists list. James, who also ranks eighth all-time in scoring, is currently the only player in NBA history to rank in the Top 10 in points and Top 15 in assists. ... San Antonio swept the Cavaliers 4-0 in the 2007 NBA Finals, garnering the Spurs their fourth championship. ... The Spurs set a franchise record for field-goal percentage in a half versus Cleveland on Dec. 11, 2004 by shooting 83.9 (26-31) in the first half. ... Next up for Cleveland is Thursday's road game in Chicago while the Spurs host Golden State on Wednesday.