W2W4: Celtics vs. Rockets (Game 22 of 82)

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Rajon Rondo and the Celtics clash with the Rockets on Friday in Houston.The Boston Celtics (12-9, 4-5 away) kick off a three-game road trip by visiting the Houston Rockets (10-11, 8-5 home) on Friday night at the Toyota Center (8 p.m., ESPN). Here's what to watch for:

* HARDEN & THE GANG: Acquired from Oklahoma City before the start of the season, James Harden is averaging 25 points, 5.4 assists and 4.4 rebounds per game. Much of Houston's offense flows through him (more on that below), but keep this in mind: Boston's defensive philosophy has long been to limit the leader of the gang, but shut down his supporting cast. One player is unlikely to beat you (barring a LeBron James Game 6 type effort), so the Celtics will likely be more focused on limiting the damage done by a supporting cast that includes Chandler Parsons and Jeremy Lin (though Lin has struggled to carve out his role, with the ball going through Harden). Houston's younger players like Patrick Patterson and Marcus Morris have taken on expanded roles as well.

* SYNERGY SNAPSHOT: Offensively, the Rockets rank 11th in points per play, according to Synergy Sports data. Harden dominates the ball, having accounted for a whopping 21.4 percent of the team's total plays (next closest is Parsons at 13.6 percent). The Rockets are best when attacking through the pick-and-roll ball handler (with Harden accounting for 46 percent of the team's plays in that situation and Lin another 26.7 percent). Harden is shooting 54.7 percent off pick-and-rolls and gets to the line frequently, which will challenge Boston's trapping. Defensively, the Rockets rank 24th. Like the Celtics, Houston struggles mightily in transition, and even in half-court sets the Rockets are a middle-of-the-pack defense. They don't defend well in the post and Omer Asik's typically stout defensive numbers have suffered on a team that's not nearly as defensive-minded as the one he left behind in Chicago.

* STREAKING THROUGH TEXAS? Even as their brand of basketball has improved, the buzz around the Celtics has been a need to string wins together and get on a roll. Boston can match a season-high three-game winning streak (Nov. 10-14) with a win on Friday night. This is a daunting trip to attempt to build some momentum, particularly with the back-to-back looming Saturday in San Antonio, but the Celtics didn't take full advantage of a softer start to the schedule (outside the seven-game-in-10-day span) and now need to string those wins together against quality opponents.

* 3-POINT DEFENSE IN FOCUS: The Rockets rank 13th in the NBA in 3-point percentage (35.8 percent), but they put up triples in volume. Houston is second in attempts (570) and third in makes (204) with Parsons (45-of-117) and Harden (40-of-116) firing away. The Celtics have been burned by 3-point shooting at times in the 2012-13 campaign and need to prevent Houston from getting hot behind the arc. The Rockets rank third in the league in scoring (104.2), but give up the most points (104.8). If the Celtics can avoid a shootout and play their recent brand of defense, they have an excellent chance to extend their winning streak.