The Celtics are headed to a deciding Game 7 against the Lakers after falling, 89-67, in Game 6 of the NBA finals on Tuesday night in Los Angeles. Here are five reasons why the Celtics couldn’t get it done in six.

1. Kendrick Perkins went down: Perkins sprained his right knee and left the game halfway through the first quarter. He fell to the ground after fighting for a rebound (an effort the Celtics hardly made in the quarter as they were outrebounded 12-5) and did not return after being helped off the court. The injury had a ripple effect on the Celtics’ inside game. Not only did the C’s suffer by losing Perkins’ presence on the court, his injury forced Rasheed Wallace into the game. Wallace, who is just one technical away from a one-game suspension, picked up three personal fouls in just eight first half minutes. With Perkins’ injured and Wallace benched with foul trouble, the Lakers got to the basket at will, including 17 points and 13 rebounds from Pau Gasol.

2. One and done: The Celtics were four quarters away from winning their 18th championship, but they let the game slip away in the first. The C’s hung with the Lakers for the first five minutes of the game and were tied 12-12 at the seven-minute mark. The Lakers then went on a run and outscored the Celtics 16-6 to end the quarter. The C’s went scoreless for over two minutes during the beginning of the Lakers tear and did not hit a shot in the final 2:11 of the quarter. The Lakers led 28-18 after one. Kobe Bryant hit five field goals in the quarter, the entire Celtics team hit just eight.

3. Ron Artest appeared: Artest’s offensive numbers through the first five games of the finals were dismal – 7.8 points, 30.2% FG, 31.6% 3PG, 46.7% FT. Paul Pierce had contained him in the battle of the perimeter players, and he had offered little help to the Lakers on the scoreboard. But Artest showed up in Game 6. He scored 10 points in the first half alone and finished the game with 15. Artest doesn’t have to be the game’s leading scorer to make a difference. He spreads the defense and draws the Celtics away from his other teammates, like Bryant, when he is making his shots.

4. The bench never stood up: Just two games ago, they won the battle for the Celtics. But in Game 6, the C’s bench was ineffective, to say the least. Five reserves combined for just 13 points, and the only reason why those numbers are that high is because the starters were benched toward the end of the blowout. The Lakers bench, on the other hand, played with the energy and hustle exhibited by the Celtics in Game 4. Sasha Vujacic swished 3-pointers, Jordan Farmar and Shannon Brown got up for highlight reel dunks. With the Perkins injured, the Celtics bench needed to step up and help the starters. That didn’t happen.

5. Lakers attacked the glass: Doc Rivers told the Celtics at the start of the series that rebounding is key. It was key in their three wins, and it was key in their third loss. The Celtics were annihilated on the glass, 52-39, as three Lakers recorded double-digit rebounds — Gasol (13), Bryant (11), Lamar Odom (10). No one on the Celtics grabbed more than nine boards (Glen Davis led the team), which was magnified by Perkins’ absence on the glass.