It's January, but Celtics-Cavaliers isn't just another game

CLEVELAND -- Friday's matchup between the Celtics and Cavaliers (8 p.m. ET, ESPN) is arguably the most important game of the NBA season thus far.

The Celtics arrive in Cleveland having lost six of their last eight games, which is remarkable when you consider they had won 19 straight and were 27-2 before the slide. The Cavaliers have lost two of their last four games, but thanks to the Celtics' struggles, hold a 1/2-game (two in the loss column) lead over Boston for first in the Eastern Conference at 28-6. And they're a perfect 18-0 at Quicken Loans Arena.

The Orlando Magic are currently tied with the Celtics in the loss column, but it will likely come down to Boston and Cleveland for the East's top two seeds, with the No. 1 seed getting the crucial home-court advantage. When these two met in the Conference Semis last season, the home team won every game. This season, the Celtics and Cavs are a combined 36-2 at home.

When two teams battle for playoff position, games against each other count double. The Celtics beat the Cavs on opening night in Boston and they'll meet twice more in the regular season before likely facing again in the playoffs.

Boston Celtics: 29-8 (11-6 on the road), Second in East
Pace: 89.7 possessions/game (17th)
Offense: 111.2 points scored per 100 possessions (7th)
Defense: 101.1 points allowed per 100 possessions (2nd)

Cleveland Cavaliers: 28-6 (18-0 at home), First in East
Pace: 88.6 possessions/game (23rd)
Offense: 114.5 points scored per 100 possessions (1st)
Defense: 100.6 points allowed per 100 possessions (1st)

1. What's wrong with the Celtics?
In short: Everything. Their offense and defense have been equally bad of late, and they're not rebounding, either.

Offensively, the Celtics are shooting worse, turning the ball over more, not getting into the paint and not getting to the line. On defense, the C's are letting opponents shoot at a much higher percentage and aren't forcing as many turnovers.

The offense will come and go. It's an 82-game season and shooting slumps happen. But the defensive falloff has to be a concern for coach Doc Rivers. Defense is what the Celtics hang their hat on; when they aren't getting stops, they're vulnerable.

2. Is there a particular Celtic that's playing bad?
If you're going to point a finger, aim it at the backcourt. Ray Allen is shooting just 39 percent from the field since Christmas, and Rajon Rondo has had some ugly performances. Paul Pierce, meanwhile, has been on fire, shooting 55 percent, including 19-for-33 from 3-point range over the last eight games.

3. What are the Cavs doing differently this season?
Offensively, they're shooting better. Interestingly, they're shooting worse from 3-point range, but shooting more treys. The real difference is inside the arc, though. Last season, the Cavs shot 46.3 percent from two-point range. This season, they're shooting 52.5 percent from that range. They're also committing fewer turnovers while running more.

Defensively, the Cavs are forcing a lot more turnovers. They're also blocking more shots and contesting shots at a much higher rate.

4. How ugly could this game get?
Very. These are the two best defensive teams in the league, and you know (despite recent struggles) both are going to bring it tonight. The Celtics can erase the frustration of the last eight games with a big win over the Cavs. And a Cleveland win would cement the Cavs as the best team in the East right now. This is not just another game.

Expect the defenses to be suffocating and both offenses to struggle as they did when these two met in the playoffs back in May. Two of those games were won by a team that scored 76 points or less.

5. What matchup should we be paying close attention to?
Keep an eye on Kevin Garnett, who will likely be guarded by Anderson Varejao. Garnett had a big series against the Cavs last May, averaging 19.6 points on 54.5 percent shooting. This season, when K.G. shoots better than 50 percent, the Celtics are 18-1. If he's cooking offensively, the Celts are usually at their best.

6. What are the chances that this is a preview of the Eastern Confernce Finals?
Pretty good. But the Magic will have something to say about it come May. The Magic were 3-1 against the Cavs last season and have split four matchups with the Celtics over the course of the past two seasons (although Orlando did lose its first meeting with Boston this year).

Orlando still has six more meetings with the two teams, so stay tuned. Of course, in the postseason, both the Celtics and Cavs will have the experience advantage over Orlando.