Watch It! – Celtics at Cavaliers

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Here are five things to watch out for when the Boston Celtics and the Cleveland Cavaliers meet at 8 p.m. tonight at Quicken Loans Arena.

Biggest Back-to-Back Test

Tonight, the Celtics will cap off what will arguably be their toughest back-to-back of the season.

Less than 24 hours after ousting the previously undefeated Chicago Bulls, Boston will now be tasked with facing the defending NBA champion Cavaliers.

There are a few other difficult back-to-backs remaining, such as a Warriors-Pistons back-to-back in two weeks and a Cavs-Hawks back-to-back in April, but tonight’s challenge will be heightened by Boston’s injuries.

Al Horford will miss his second straight game with a concussion, while Jae Crowder, who sprained his left ankle last night against Chicago, is expected to miss at least a week.

The Celtics are also still without forward Kelly Olynyk (shoulder), so they will be very shorthanded against a fully healthy, unbeaten Cleveland team.

Who’s Got LeBron?

Jae Crowder has proven to be Boston’s most competent defender of LeBron James, but since he’ll be sidelined tonight, the Celtics will have to rely on a committee of defenders to try to stop The King.

Marcus Smart is one guy that will need to step up, and while he’s four inches shorter than James, he’s proven to be able to defend much larger players in the past. Smart’s suffocating on-ball defense and lateral quickness should be able to help him in this matchup.

Rookie Jaylen Brown may be thrown into the fire to defend James as well. The 20-year-old has already shown NBA-ready defensive skills, though this will be the challenge of a lifetime considering he’s played as many NBA games as James has won league MVPs.

Jonas Jerebko is one other guy who has shown the ability to limit James on the offensive end, as he has switched onto James in the past and used his length and speed against him.

It won’t be easy defending James without Crowder, but Boston certainly has guys who are willing to step up and give it a go.

C’s Lights Out Shooting

One of the main areas that Brad Stevens wanted his Celtics to improve in this season was their shooting efficiency.

The coach must be very satisfied through the first four games, because Boston currently finds itself leading the league in field goal percentage with a 49.8 percent clip.

Last season, the Celtics shot 43.9 percent from the field. Only the Suns, 76ers and Lakers finished with a lower efficiency from the field.

Boston is also shooting 40.7 percent from 3-point range, which ranks them fourth in the league. Their mark last season from that distance was 33.5 percent, which was the third-lowest percentage in the NBA.

Four games is a small sample size, but Boston’s shooting out of the gate is certainly trending in the right direction.

Johnson’s Offensive Boost

One guy who is contributing mightily to Boston’s shooting prowess is Amir Johnson.

The 11-year veteran currently owns the third-highest shooting percentage (64.0 percent) in the league among qualified shooters, and he’s coming off of one of the most impressive offensive performances of his career.

Johnson shot 9-for-11 last night against Chicago, including a career-best 4-for-4 from 3-point range.

The big man’s contributions will be needed again tonight, especially since Horford remains sidelined.

East’s Last Perfect Team Standing

The Cavaliers (4-0) are the only team remaining in the Eastern Conference that have yet to be beaten. They’ve delivered losses to the Knicks, Raptors, Magic and Rockets so far.

The last time Cleveland started a season 5-0 was in 1976, which was roughly six months before head coach Tyronn Lue was born.

Boston, however, has a knack for knocking off unbeaten teams this season. The C’s beat Brooklyn on opening night, a 2-0 Charlotte team and a 3-0 Chicago squad, which accounts for all three of their wins.

That being said, ending Cleveland’s unbeaten mark will undoubtedly be Boston’s biggest challenge so far.