After J.R. Smith was yanked late in the second quarter after another airball, a Garden fan was overhead shouting: “Smoke another one.’’

The stench was evident Sunday in Smith’s season debut after serving a five-game suspension for failing three marijuana tests. The big ovation Smith received when he checked into the game with seven minutes left in the first quarter quickly turned to boos or groans after each miscue.

Smith missed his first six shots and finished 1 of 9. He nearly committed as many turnovers (four) as points scored (five). Rehabbing from knee surgery, he had played just 12 minutes in one preseason game before the suspension kicked in, but he wouldn’t use anything as an excuse other than he didn’t have it.

“I didn’t feel rusty at all,’’ said Smith, who has admitted conditioning will be an issue early on. “I just missed a lot of shots, Didn’t get to the basket like I wanted to. Overall I didn’t have a good game. We kind of had a lid on the rim today.’’

Mike Woodson is mulling whether to start Smith as a promotion for his Sixth Man Award winner from 2012-13. He still could start him Wednesday in Atlanta as Iman Shumpert struggled Sunday and the Knicks coach hinted at lineup changes.

But Woodson said he anticipated a rough debut.

“You kind of expected that,’’ Woodson said. “The young man hasn’t played. He played the one exhibition game and he’s had some practices. Exhibition and practice is not the same as a real game.’’

Smith was 0-for-4 with two turnovers in the first quarter. Smith had his worst moment in the final ticks of the first period as dribbled down the clock, looking for the final shot. Instead, as he started his drive, he coughed up the ball. San Antonio scored at the buzzer but it was waived off.