The Celtics will never get over Game 7.

It haunted them over the summer and put them in a “dark place,” as Kevin Garnett called it. It influenced their offseason moves as Danny Ainge sought to add size, size and more size to the roster. It stayed with them through training camp and has served as a constant reminder to push them through the never-ending regular season.

Sunday’s game with the Lakers is the first time the Celtics will step back into Staples Center since Game 7. While nothing can ever make up for what was arguably the biggest loss in franchise history, the stakes remain high.

Here are five things the Celtics need to do to beat L.A.

OWN THE GLASS

This point can’t be stressed enough. The Celtics lost the NBA championship because they were a poor rebounding team and in Game 7 the Lakers grabbed 23 offensive rebounds. Maybe Kendrick Perkins would have made a difference, but this was a season-long issue for the Celtics and it caught up with them at the worst possible moment.

Pay no attention when people say the Celtics are the worst rebounding team in the league this season. They are the worst offensive rebounding team in the NBA, but that is a very different thing.

The number that matters is defensive rebounding percentage, and they rank a respectable ninth in that category. Again, this is a far better way to judge a team’s effectiveness on the glass than total number of boards because it accounts for the number of shots attempted.

Defensive rebounding has been the constant theme for the Celtics this season and until Kevin Garnett missed nine games with a calf strain they were on their way to re-establishing themselves on the boards. Since Garnett has been out – and even since his return – the Celtics have slipped.

Before Friday night’s ejection, Garnett was in the midst of his strongest night on the boards since his return. He had nine defensive rebounds and grabbed almost half of the available defensive boards when he was in the game. That’s the kind of effort the Celtics will need against Pau Gasol, Andrew Bynum and Lamar Odom.

RAJON RONDO, STAND UP

Like the rest of his teammates, Rondo is coming off his worst game of the season. He made only one shot in six attempts against the Suns and had more turnovers (seven) than assists (six). Turnovers have been a problem for Rondo recently. He had six against Portland, four against Washington and five versus the Jazz.

Against the Lakers, Rondo will face his own version of torment because Kobe Bryant will play 10 feet off him to keep him out of the lane and dare him to shoot jump shots. What makes the Lakers defense so effective against Rondo is that Bryant is adept at playing the passing lanes and cutting off his angles to make passes.

During the finals, the Lakers big men also made an adjustment in that they waited for Rondo to make a decision, and essentially expected he would look to pass instead of trying to finish when he got in the paint.

The Celtics have been working sets that get Rondo the ball in the high post at the elbows, which forces the action to him rather than having him get there on his own. It will be interesting to see if this counter proves effective against the Lakers.

The Celtics can beat the Lakers without Rondo playing his best, but it’s obviously easier for them if they can get him out in space in transition and not bogged down in the halfcourt. Again, that’s why it’s so important to control the glass.

CONTAINING KOBE

The obvious answer is Ray Allen, who played the best individual defense of his life in last year’s finals against Bryant. But as Zach Lowe from SI’s Point Forward blog pointed out, the Lakers have used Bryant at small forward in a lineup with Shannon Brown and Steve Blake at times.

The Celtics could counter with their own small lineup with Rondo, Nate Robinson and Allen, something they used extensively in a blowout win over the Cavs earlier this week. They could also use Paul Pierce on Bryant, but Pierce is battling a set of minor injuries.

Bryant remains the dominant focal point of the Lakers offense, using over 34 percent of the team’s offensive possessions when he is in the game -- the highest rate in the league. There has been some question as to whether that’s the right approach for the Lakers, considering they have a plethora of offensive options, but that remains the way they play.

Whoever draws the assignment will be in for a long afternoon.

KG vs. GASOL

It was a simple, and honest, statement that took on a life of its own. As part of a very long answer, Pau Gasol suggested the Kevin Garnett had lost a step. That was true in June of 2010 and it became even more obvious when Garnett could do little to change the perception once the statement was presented to him as a challenge.

Much has changed for Garnett since then, but all eyes will be on this matchup to see just how far he has come. Gasol remains the best offensive post man in the world, and while Celtics fans may be loathe to admit it, he is far from soft.

This is a huge test for Garnett who is once again under scrutiny for his low-blow of Phoenix’s Channing Frye. This came after Garnett received a chop-shot to his thorax from Suns’ forward Mickael Pietrus.

Since his return Garnett has appeared even edgier than usual. He’ll need to have his focus throughout Sunday, because Gasol is perhaps his toughest matchup.  

MATCH LAMAR ODOM’S ENERGY

It took Lamar Odom the better part of his career to find his calling, but he has found it in the Lakers system. His versatility is the key to Los Angeles' frontcourt rotation and against the Celtics in the finals the formula was simple. When Odom played well, the Lakers won. When he didn’t, it opened the door for the Celtics.

Odom is having one of the best seasons of his career, averaging 15 points, nine rebounds and three assists per game while shooting 57 percent from the floor.

Containing Odom will fall to Garnett at times, but it is mainly the responsibility of Glen Davis, who is having his own career season. Davis strained his hamstring Friday night and missed the second half of the Suns game. If he is limited in any way it would be a major blow for the Celtics.

In addition to Odom, the Lakers also have the very effective backcourt duo of Brown and Blake in the mix. Brown has become an instant-offense threat off the bench, while Blake is a steady 3-point bomber.

This would be an ideal situation for Delonte West, but West is sidelined with a broken wrist and still weeks away from returning. The onus is on Nate Robinson and Marquis Daniels to provide something of value to the Celtics second unit, which has noticeably struggled all season.

With all that, there are a number of other X-factors in this game including Ron Artest’s ability to defend Pierce (and get under his skin), whether Shaquille O’Neal can stay out of foul trouble and how much Kendrick Perkins and Andrew Bynum can contribute.

As always when these two teams plays, there is no shortage of storylines, subplots, strategy and intrigue. The Celtics will need to be at their best to get past the Lakers and earn a small measure of redemption for last year's soul-crushing loss.