Should we consider Boston a title contender now?

The play for the first three quarters of this season confirmed the conventional wisdom going in — the Miami Heat and Chicago Bulls were the class of the East, everybody else was a couple of steps back.

But in the past 10 days, the Boston Celtics have thumped the Heat twice. And although the Bulls beat the Celtics in that time frame, anybody who has seen Chicago of late and waited for the return of Derrick Rose knows the Bulls are not at their peak. They look vulnerable.

With their play of late, do we have to consider the Celtics contenders?

Yes. But for them everything needs to go right — health, good matchups. Which is pretty much what everyone said about Dallas before last playoffs and…

Boston has certainly hit its stride of late. That all starts with their defense — that has been their calling card during this run, it had taken a small step back in recent seasons but this year they are back to being the best defensive team in the league. When you defend like that, you have a chance every night in the playoffs. And Kevin Garnett is still at the heart of that (and he’s scoring well of late, too).

The Celtics also are getting great play from their role players — against the Heat on Thursday Greg Stiemsma was a force in the first half, defending at the rim and knocking down midrange jumpers. The emergence of Avery Bradley has allowed Doc Rivers to bring the scoring punch of Ray Allen off the bench, giving the Celtics frightening depth. Brandon Bass is an upgrade from Big Baby. Even guys like Sasha Pavlovic are stepping up.

Rajon Rondo keys the offense — he is the guy who has to create for others, to get some easy buckets in transition, he has to keep the ball moving. Boston has become an offense that finds the mismatch and takes what the defense gives them. Miami gave them jump shots, Boston was disciplined and knocked down the looks. Boston also runs some nice Paul Pierce/Garnett pick and rolls, plus they move off the ball well.

It may come down to matchups — Boston clearly gives the Heat trouble. Boston’s ball movement exposes the help rotations of the Heat, then Boston has guys who can knock down the jumpers. It was not a lack of effort from the Heat Tuesday night, they just struggle with Rondo and Boston. Chicago — from the same defensive school as the Celtics — may be a tougher matchup for the Celtics. And it’s also the more likely second round contest.

But right now, when you talk of teams that have a chance to come out of the East, you have to mention the Celtics. They have earned their way into the conversation.