Celtics vs. Nets preview: Atlantic Division rivals renew hostility in Christmas Day opener

Last year's Christmas Day NBA marathon began with a thriller at Madison Square Garden between the New York Knicks and Boston Celtics. You can expect this year's Christmas Day opener between the Celtics and Brooklyn Nets to yield similar fireworks. Both teams enter the game in similar places in the Eastern Conference's hierarchy, and both have salty feelings left over from the team's previous matchup.

Ah yes, that previous matchup. When these two teams last played in Boston in late November, Rajon Rondo went after Kris Humphries following a hard foul on Kevin Garnett. A mini-brawl followed, resulting in ejections for Rondo, Humphries and Gerald Wallace.

Rondo was later suspended two games, a punishment that seemed relatively light at the time, and Humphries tried to poke fun at Rondo by posting this picture on his Twitter account. It's safe to say both teams will have that incident on their minds as they do battle one month later.

Then again, the Nets are in a very different place than they were in late November. The Nets' 95-83 win in that game pulled them to 10-4 on the season, but after defeating Orlando two nights later, they've lost nine of their last 12 games. An injury to Brook Lopez didn't help, but most of the Nets' issues are internal. Deron Williams is playing poorly and squabbling about the team's offense, Joe Johnson is sometimes struggling to fit in and the team alternates between brilliant and maddening play on both ends of the court.

These are the growing pains one can expect from teams with so many new parts, but the Nets entered the season with high expectations. There's no time to flounder like this.

Meanwhile, the Celtics have their own issues. They've lost four of their last five games, including a frustrating overtime defeat to the Milwaukee Bucks on Friday. Paul Pierce has played beautifully recently, but the rest of the team is having its issues. They've never figured out how to succeed without Kevin Garnett on the floor, and even Garnett himself has looked old at times. The team's once-vaunted defense is just 11th in the league in points allowed per 100 possessions, and critical bench players like Courtney Lee, Jason Terry and Jeff Green have performed below expectations.

You'd think the Celtics will eventually get it together, because they always do. Underwhelming regular seasons followed by longer-than-expected playoff runs have become their trademark. But this team has many more new parts to integrate than past units, and they haven't defended like Celtics teams of the past. They could really use a win on Christmas on the road to jump-start a lagging season.

Game time: Noon ET.

TV: ESPN.

STAR WATCH: Expect to see the Nets throw lots of different players on Pierce, who has been on fire recently. Keith Bogans might start on him, but don't be surprised to see Wallace, Jerry Stackhouse and even Johnson get their chances.

X-FACTOR: Andray Blatche continues to be a revelation off the bench for the Nets, and there's really nobody the Celtics have off the bench that can slow him. The Celtics often stagger Garnett's minutes so that he plays a lot with their second unit, so I would expect to see that happen again to prevent Blatche from dominating the second and early-fourth quarters.

KEY TREND TO WATCH: The Nets have begun going to smaller lineups more recently with Gerald Wallace playing power forward, and it's enabled them to spread the floor more easily. Will the Celtics counter by playing Green more with Pierce and Garnett, or will they continue to give minutes to Brandon Bass and Jared Sullinger?

PREDICTION: Nets 91, Celtics 88.