"Oh yeah, it would've been over," Smith said after Tuesday's practice. "I'd have been playing golf today."
The NBA suspended Smith for Game 4 after the star guard threw an elbow at Jason Terry's chin late in Game 3.
Smith watched on television Sunday as the Celtics defeated the Knicks 97-90 in overtime to avoid elimination and extend the series. Smith also watched Terry score nine points in overtime.
Asked about Terry on Tuesday, Smith said, "Who? I don't even know who that is."
The Knicks' bench scored just seven points in the loss, a clear indication that they were hurt by Smith's absence. Carmelo Anthony shot just 10-for-35 and seemed to miss Smith, who draws attention from opposing defenders.
"It was very tough to watch," Smith said. "Especially that first half. I mean, from the turnovers to missing shots. ... It wasn't the easiest thing ever.
"I wasn't pleased with it. My teammates wasn't either. I'll get the chance to make up for it tomorrow."
The Knicks can close out Boston in Game 5 on Wednesday and win their first postseason series since 2000.
"It's a must," Smith said of Game 5. "We're playing at our building. We're planning on not losing any games at our building, so I mean we've got to get this thing over as fast as we can so we can get (Jason Kidd) his rest, Melo his rest, and get prepared for the next series."
Smith, the NBA's Sixth Man Award winner, would not offer his opinion on the one-game suspension.
"I can't really say what my reaction was," he said. "It won't be good for me or my team."
Smith said he learned a lesson from his suspension.
"Yeah, don't throw elbows," he said.
Ian Begley is a regular contributor to ESPNNewYork.com.