There hasn’t been much to worry about with the Celtics this season, even with all the injuries. One way or another they have managed to patch up the lineup with a Semih Erden here or a Luke Harangody there and continue to roll right along.

But if there has been a negative trend, it’s this: The Celtics have lost 10 games this season, and five have come against teams with losing records.

To put this in perspective, the Celtics are 15-5 against teams with losing records, while the Miami Heat are 23-3. The flipside is that the Celtics are 18-5 against teams over .500, while Miami is only 8-10. So while the Celtics are routinely beating the best teams in the league, they have also suffered the occasional misstep.

Basically, if the Celtics took care of business in the games they were supposed to win, they’d be the Spurs who are 21-1 against sub .500 teams and leading the West by a healthy margin.

The latest misadventure happened Saturday night when the Celtics blew a 15-point first quarter lead and scored just 27 second-half points in a loss to the Washington Wizards. There were several mitigating factors. It was the second night of a back-to-back. It was their first road game in two weeks and they were without Shaquille O’Neal. Ultimately, however, there wasn’t much justification for blowing a winnable game. 

The first bad loss came in the second game of the season, to the Cleveland Cavaliers. Again, it was a back-to-back, and came on the heels of their much-hyped opener against Miami. There was a loss at Toronto where they forgot to play defense. One against Detroit when Kevin Garnett got hurt, and an all-around meltdown against Houston where nothing went right.

“If you look at the whole season, we’ve had a terrific season so far,” Doc Rivers said Monday after the team’s practice. “But if you look at that terrific season, we’ve had some bad losses. Those are tough losses for a team that shouldn’t lose those games. More lessons learned and we’ve got to keep teaching them.”

The essential lesson is this: When the Celtics play their offensive game – with crisp passing and movement as the hallmarks – they are almost impossible to beat, because their defense has been there almost every night. When they don’t, they’re vulnerable.

As with everything in the 82-game marathon, the short-term issues feed into the big picture. A bad night in Washington may be an isolated instance, but it all plays into the long-term goal. “The way to get up [for these games] is to look up at the banners and think about homecourt,” Rivers said. “That’s what should motivate you.”

The Celtics have a three-game lead on Miami in the loss column for the best record in the Eastern Conference. They won’t admit it because there’s too much season left but that’s the only positioning that really matters.

With that, there are easily correctable issues for the Celtics. The Wizards loss was a classic case of fool’s gold. After scoring 35 points in the first quarter, the offense ground to a halt. The litany of sins included too many jump shots, not enough touches on the post and too little urgency in getting into sets.

Rivers didn’t like the pace, but he was quick to deflect criticism from his point guard, Rajon Rondo. By his count there were 10 times when Rondo was up the floor, but had to wait while players walked into position.

The Celtics don’t have a lot of players who can get their own shot when the 24-second clock is winding down, so it’s imperative that they get into their sets quickly and use the time to set up the best possible shot. (You can see how their shooting numbers sink like a stone late in the shot clock at 82games.com).

The result was too many long jump shots, 42 to be exact, and Rondo, Glen Davis and Kevin Garnett were a combined 3-for-16 from the outside.

All of which brings us to the present. The time is right to get those issues straightened out because the Celtics welcome the woeful Cavs to the Garden Tuesday night before heading out on a west coast trip that will feature a Sunday afternoon showdown with the Lakers.

But, first things first. Since starting the year with a respectable 7-9 record, the Cavs have lost an astonishing 27 of 28 games and are currently riding a 17-game losing streak. Along the way they scored 57 points in a 55-point loss to the Lakers and have scored 100 points just three times since the losing began.

Losing LeBron James obviously set the franchise back years since they have a number of players on long contracts who were brought in specifically to play with LeBron, but they have also been crippled by injuries to Mo Williams and Anderson Varejao.

“Varejao is their Kevin,” Rivers said. “He’s their energy guy. The guy does everything and that’s a tough loss. Losing LeBron hurts too, but losing LeBron and Varejao, that’s a major blow.”

In other words the Celtics have an excellent chance to get back on the winning side Tuesday night. It would make their lives much easier if they simply played their game. 

“I very rarely worry about the opponent,” Rivers said. “I worry about ourselves and when we play right, I think it gives us an excellent chance to win games and when we don’t, anyone can beat us. That’s been proven this year.”