A lot has been made about the Lakers' inability to hang on to a lead in games 4 and 5. I credit Boston's ability to lock down the Laker offense and force them to play to their greatest defensive strength, which is help defense. The Lakers at times have looked stagnant compared to earlier in the post season when they dominated their opponents with efficient passing for high percentage shots and lots of off-ball movement. The hustle and defensive prowess of Boston has severely hampered this ability.
Despite pulling off one of the all time greatest comeback in SPORTS (not just the NBA, but SPORTS in general) history in game 4, the Celtics rallied hard in game 5 but couldn't quite make it over the crest. You could argue that the lack of Kendrick Perkins affected the Celtics' post defense, forcing KG into early foul trouble. However, I blame none other than Garnett himself. His stats weren't terrible (13 points, 14 rebounds), but it was obvious that a better performance from Garnett could've won Boston the Championship. KG blew an opportunity to tie the game late, and the Lakers pulled away for good.
At the end of the regular season, I fully expected KG to be an absolute beast in the post season, and while he hasn't been a disappointment, he hasn't been quite as beast as I predicted. Ray Allen has been Boston's most consistent player in the Finals, and Pierce has been a force. The Celtics needed KG in game 5, and KG failed to step up.
Boston plays with much greater confidence at home, and the task that lays ahead of the Laker's is huge. Allen and Pierce did everything they could in game 5. The only other thing Boston needs in game 6 is for KG to show up.