Defense will dictate C's success

Here's what we've learned about the Boston Celtics through three games this season: When the team plays inspired defense, it can compete with anyone. When it doesn't, it's liable to get run out of the gym.

Monday's game in Dallas gave us a glimpse at both sides of the coin. The Celtics went through the motions in the first half and a supremely talented Mavericks offense torched them for 67 points -- including a 40-point first quarter -- while shooting 63.4 percent overall and 71.4 percent beyond the 3-point arc before the intermission.

The Celtics trailed by as much as 31, and were down 26 at halftime. During his television interview walking off the court, coach Brad Stevens was asked about what needed to change defensively and sniffed, "Well, we haven't really done anything [defensively]."

Stevens implored his team to "just go play" and that included having the team's three-guard lineup of Rajon Rondo, Avery Bradley and Marcus Smart ratchet up the backcourt pressure for much of the second half. Sparked by their defense, especially that of rookie Smart, the Celtics trimmed 14 points off their deficit in the third quarter and surged within a point in the final minute only to have the Mavs fend off their charge in a 118-113 loss.

All the typical rally caveats apply here, most notably how teams with a 26-point halftime lead have a way of taking their feet off the accelerator. Regardless, Boston showed itself what's possible when it plays a feisty brand of defense.

After Monday's game, Stevens found a balance between praising his players for their comeback effort and scolding them for having to rally from such a monster deficit. "I don't want to make it like it's the comeback of all comebacks," Stevens told reporters in Dallas before adding, "It doesn't change the fact that you can't play like that [in the first half]."

And so when the Celtics watch game film of Monday's tilt, players likely will see more of their first-half lapses than second-half highlights. Make no mistake, there are positives to be plucked in how Boston bounced back -- especially after the team did not respond well to adversity during a lopsided loss in Houston on Saturday -- but Stevens must hammer home how Boston cannot dig itself such a deep hole.

So Stevens will show his team the obvious differences in its play and defensive tenacity between the first and second halves. Stevens himself has maintained that Boston cannot expect to pressure the ball for 48 minutes, but they wouldn't have had to do it for even 24 on Monday if they weren't playing from such a deficit. Expending all that energy on the comeback might have left them without enough gas in the tank to finish off the surge in the final moments.

Ultimately, the goal for Stevens is to find a way to get his troops to play with the sort of defensive energy and focus displayed in the second half without needing a huge deficit to ignite them. The Celtics played like that at times in the season opener and emerged with a lopsided win over Brooklyn. Things didn't go nearly as well in Texas, but it will be interesting to see if the team can build off those two losses, especially when defending Atlantic Division champ Toronto visits TD Garden on Wednesday.

The way Smart's defensive energy changed the game in the second half cannot be understated. Playing in front of a horde of family and friends in Dallas, the Texas native's stat line won't jump off the page -- seven points on 3-of-7 shooting with six rebounds, three assists, a steal and a block -- but he was spectacular in the second half.

Heck, Smart even took on the challenge of guarding Mavs star Dirk Nowitzki at times in the fourth quarter. At one point, Smart tried -- but failed -- to draw a charge as Nowitzki backed him down off a switch. He got the last laugh moments later. Smart took a feed from Rajon Rondo on the left wing and Nowitzki didn't sprint out fully to contest. Smart took a couple of dribbles then boldly stepped back behind the 3-point arc and splashed a high-arcing triple over a lunging Nowitzki to make it a one-possession game with 3:37 to play.

Smart's offense is still a work in progress, but his defensive impact has been immediate. And the way he's embraced going against bigger, star-caliber players such as Nowitzki and Joe Johnson only underscores his potential to be a game-changing defensive presence.

Smart's second-best offensive moment of the game? That came when he produced a slick behind-the-back pass off a scramble under the basket that led to a Jared Sullinger layup. Smart showed great awareness to simply chase down the ball and quickly feed it to Sullinger in one smooth motion.

The best part of Jeff Green's 35-point outing: That 11 of his 28 attempts and half of his 14 makes came at the rim. Green is at his best when he's aggressive going at the basket. What's more, four of his seven rebounds came on the offensive side, showing that he was around the hoop more often than we've typically seen.

What's amazing about Bradley's 32-point showing was that three of his four second-half misses came at the basket. Bradley was 7-of-8 shooting from outside the restricted area and everything he put up -- from the mid-range and beyond the arc -- seemed to splash through.

And finally ...