Four things to watch for in Celtics-Rockets showdown (8:30 p.m., ABC)

HOUSTON -- The Celtics face their toughest remaining test of the regular season on Saturday night in a national showcase against the Houston Rockets. With both teams coming off two days of rest leading into the showdown, this is a matchup that likely means a bit more than usual to both squads given the national attention, even if neither side will admit it publicly. It’s also a great measuring stick for Boston after beating up on inferior competition following the All-Star break.

While the Celtics took game one of the season series after a miraculous 27-point comeback at the TD Garden, both squads will look far different for this contest. Boston will have a pair of valuable wing defenders available in Jaylen Brown and Semi Ojeleye this time around. The Rockets will be getting a bigger boost, however, thanks to healthy Chris Paul and Clint Capela.

“I don't think their stuff is necessarily different as far as actions and things like that,” Brad Stevens explained on Saturday when asked about what changed with Paul and Capela in the lineup. “We've talked about it with Kyrie being able to play off the ball. If Harden has to have the ball all 48 minutes, that's hard. That really wears on you. To have a guy next to him that's a Hall of Fame caliber player, that's crazy to think about.

“They have 48 minutes of All-Star play at point guard when those guys are out (there). At the end of the day, they make it really tough, because they can both play off the ball and with it. They don't change their actions a ton. Capela gets a lot off the spread pick-and-roll, he gets a lot off of effort and energy. They do run a couple of cool wrinkles for him out of timeouts where they will back screen for him and lob it. It's easier said than done because you're preparing for it, you see it and you know it's coming. At the same time, who you helping off of? That's what they put you in a bind with.

With the Rockets nearly unbeatable (one loss all year with a healthy starting five) at full strength, the Celtics will have their hands full Saturday night. Here’s a few things to keep an eye on as they attempt to pull off the upset and end Houston’s 14-game winning streak.

1. Make the Rockets over reliant on the 3-ball: It’s a weird suggestion for a team that shoots more 3s than anyone else in the NBA already. However, it’s the lesser of two evils as far as the Celtics are concerned. If you overplay the Rockets at the 3-point line, you open up the paint, and that’s where Houston is most dangerous. They can drive and kick, find open looks for Clint Capela on rim runs, and get to the free throw line at will (No. 1 in FT rate all year). That’s a recipe for disaster for the Celtics. Assuming Boston can keep Houston out of open corner 3 looks, they should do their best to encourage the Rockets star to settle for longer looks. Houston is just 11th (37 percent) in 3-point shooting accuracy in the league, and one of their best shooters from deep (Ryan Anderson) is out with a hip injury Saturday night.

Stevens shouldn't want to give James Harden and Chris Paul uncontested looks, but the Celtics should be willing to live with names like PJ Tucker and Luc Mbah a Moute taking contested 3s as the shot clock runs down. Eric Gordon also takes a ton (10 per game) despite shooting 33 percent on them. The Rockets’ offense is so good that you can’t take everything away and the Celtics have the best 3-point defense in the league (33 percent) for a reason. They should try to use that to their advantage tonight and live with the results. Half of Houston’s shot attempts (43) in the first meeting this year came from downtown and they shot just 32 percent on them. Brad Stevens should try to lure them into that trap again.

2. Get into James Harden’s head again: The Celtics have done a nice job of this over the past few seasons. Clearly, this is just the assignment for Marcus Smart. He won’t start, but he’ll spend the majority of 48 minutes guarding the MVP candidate, while Brown and Ojeleye will chip in as well. Harden will get his points no matter what, but the question is whether the Celtics can lure him into mistakes. He has averaged 8.3 turnovers per game over the last two seasons against Boston, which helps take some of the shine off his overall production (33 ppg, 9.7 apg) in those same contests. Frustrating Harden has enabled the Celtics to win three of their last five contests against Houston. He has obviously had a lot of help this year with Chris Paul, but the shooting guard is still the straw that stirs the drink on most nights. Whether it’s drawing offensive fouls or forcing errant passes, the Celtics need to prevent the Rockets supporting cast from getting wide open looks. Since Harden is the guy who makes that happen, they need to prevent him from getting into a rhythm.

3. Don’t go small too much upfront: The Rockets have an elite defense themselves, and that should put the improved Celtics’ offense to the test in a tough road spot on Saturday night. While it may be tempting for Brad Stevens to go small up front and stay away from his traditional bigs for the majority of 48 minutes in order to spread the floor, the presence of Aron Baynes and Daniel Theis should prove to be valuable from a rim protection standpoint on defense (don't expect much time for Greg Monroe). When the Celtics’ fell behind by 26 points in their first meeting against Houston, the lack of interior help defense from small ball lineups dug Boston a deep hole. Ultimately, the C’s will stay small in crunch time to combat the Rockets shooting ability all over the floor and allow better defenders to stay with Harden and Paul on switches. Before that time arrives though, Stevens should give his bigs a chance to anchor the defense in this game and keep Clint Capela from taking over with lobs and on the glass. They are going to need strength inside to combat the double-double machine.

4. Avoid testing Houston’s elite defenders with isolation ball: The Rockets are a different team this year not only because they have Chris Paul manning the point, but because their wing defense is better than ever with the additions of PJ Tucker and Luc Mbah a Moute. Both of those guys were lockdown defenders in their primes, and they aren’t too far removed from those days. The presence of that duo, along with Trevor Ariza, makes this group a challenging one to score on both nights. The C’s are going to have to keep the ball moving within the offense to have a chance to keep pace with Houston’s high-powered offense. Settling for isolation ball against these guys is a bad idea, even though that’s in the DNA of a lot of players on this roster. The pressure tonight is on guards like Smart and Irving to keep the C’s offense rolling, otherwise it could be a long night for this crew at the Toyota Center.