Brian Babineau/NBAE/Getty

A familiar sight for Boston: The Spurs coming away with the defensive rebound.BOSTON -- The Boston Celtics narrowly avoided being only the second team in the last quarter century to be shut out on the offensive glass when Brandon Bass tipped home a Paul Pierce miss with 88 seconds remaining in Wednesday's 112-100 loss to the San Antonio Spurs at TD Garden.

That was Boston's only offensive carom of the night, but Rivers insisted he's not concerned by the low number.

“Honestly, we shot 53 percent, [so] there’s not going to be a lot of offensive boards," said Rivers. "You know what I mean? So I’m not that concerned by it. [The Spurs] shot 58 percent and they had six. So, you’re a big believer in offensive rebounds I think; I’m not. Listen, like I said, you can pick on that all I want. That is a number I rarely look at, offensive rebounds. Statistically, it holds up. I can tell you, you don’t offensive rebound, you stop transition, you win more games than when you get offensive rebounds. I can guarantee you that on those stats."

The Celtics' defensive philosophy in recent seasons has been to eschew second-chance opportunities with the goal of getting back and forcing opponents to play in a halfcourt set. That's helped make Boston one of the league's top defenses throughout the Kevin Garnett era. Heck, Boston had the lowest offensive rebound percentage (19.7) in league history last year.

Boston surely wants to grab more offensive boards, and rookie Jared Sullinger has earned heavy playing time with that in mind. But Rivers refuses to allow more transition opportunities and it's easy to understand why: The Celtics rank dead last in the league in points allowed per transition play.

"Obviously, we would like to get some offensive rebounds, and if we’re under there we’ll take them, and we didn’t get any, but that is not why we lost," said Rivers. "Let me just say that. Offensive rebounds are the least of our problems.”