By A.Sherrod Blakely
CSNNE.com
MIAMIThe Boston Celtics' Big Three have seen a lot during their run together, having experienced just about every high and low a championship-caliber team can imagine.
But two games into their Eastern Conference semifinal battle with the Miami Heat, and this battle-tested group is now in unfamiliar terrain.
Tuesday's 102-91 loss to the Heat puts the Celtics in a 2-0 series hole, the kind of deficit few teams ever rally from -- and one this group has never experienced.
LeBron James had a huge night with a game-high 35 points and 7 rebounds. Dwyane Wade was a problem for the Celtics as well, scoring 28 points to go with 8 rebounds and 3 assists. The third member of Miami's Big Three, Chris Bosh (17 points, 11 rebounds) had a solid game as well.
Boston was led by Rajon Rondo's 20 points and 12 assists.
Their play, coupled with some solid play from their supporting cast, has the Celtics two losses away from the end of their season.
Boston Celtics
"This is it," Boston center Jermaine O'Neal told CSNNE.com following Tuesday night's loss. "We're definitely in a must-win situation now."
When the Celtics' Big Three found themselves in difficult spots before, they always had the luxury of experience to fall back on. But experience won't do them any good now.
In fact, the age gap between these two teams seems to be magnifying as each game passes.
Miami's youthful Big Three have been too fast, too strong and too dominant thus far for Boston to handle.
Because of that, the only chance the Celtics have of bringing home Banner 18 is to do what hasn't been done by a Celtics team since 1969 -- rally from a 2-0 series deficit.
"It's very difficult (being down 2-0)," said Boston's Kevin Garnett, who had 16 points. "It is what it is, and we have to deal with it. We need to go protect our home courtperiod. There isn't much to talk about. It's do-or-die."
After spending most of Game 2 trailing, the Celtics tied things up at 80-80 following a pair of free throws by Paul Pierce with 7:10 to play.
That's when Miami did what its been able to do in both games thus far - put together a back-breaking run that the Celtics can't match.
A 3-pointer by Mario Chalmers and a pair of free throws by Wade set a 14-0 Heat run in motion, a spurt from which the Celtics were never able to recover.
"The root of it still comes back to the confidence in our defense," said Heat coach Erik Spoelstra. "That we don't feel desperate that one guy has to take over and hit a home run. That we can execute and trust and if there's an open guy, we can throw it to him."
The Heat pulling away in the fourth was symbolic of the way Monday's game -- this entire series for that matter -- has played out.
Miami has played well, but has been at its best in closing out quarters, which, as you can imagine, was a topic of discussion among the Celtics following Tuesday's loss and will remain one between now and Game 3.
"One of our biggest strong points in how we play the game, is closing out quarters," said Ray Allen. "What we haven't done in these two games is close out quarters well. Whether we are down, whether we are up, or the game is tied, to finish the quarter we have given them too many points."
Finishing quarters off strong is one of the many things the Celtics have to do a better job at in Game 3.
But it won't be easy, not against a Heat team that seems to be gaining more and more confidence with each passing quarter of this series.
"For us, we just have to keep it simple," said coach Doc Rivers.
Doing that becomes easier if Paul Pierce can play.
Pierce suffered what was initially believed to be a left foot strain. However, Pierce told reporters on Tuesday that it's actually a sore left Achilles tendon.
He's not the only Celtics player hurting these days. Allen suffered a bruised chest injury after he took an elbow from LeBron James.
"No one is 100 percent this time of year," Allen said. "It is part of the game, you just deal with them. I am sure they have the same issues. You just off-days to get your body better."
And the Celtics could certainly use the time to heal, both physically and mentally, as they continue their journey through unfamiliar terrain that will test them in ways they've never been challenged before.
"We have lost a lot of different ways and won a lot of different ways," Allen said. "There is no clear-cut way to win a championship, or win during the regular season. I have learned that over the course of my career, the adversity that you face makes you who you are, and that is why we are here.
Allen added, "being down two games to zero does not scare any of us, or make us nervous. We have an opportunity to go home and play in front of our crowd and play good basketball."
A. Sherrod Blakely can be reached atsblakely@comcastsportsnet.com.Follow Sherrod on Twitter at http:twitter.comsherrodbcsn