Now comes the hard part.
The Celtics , after dropping Game 3 on their home court, have crept to within one win of their 18th title by taking advantage of the incredible energy inside TD Garden. But if they are to raise yet another banner to the rafters in the fall, they’re going to have to get it done in the hostile environment of Staples Center .
Kendrick Perkins  said the key to transferring the momentum and energy of the TD Garden crowd to Los Angeles will be mental toughness.
“It’s all mental,” Perkins said. “I think we have to go out there and take their crowd out of it early. We can’t let them get energy going in the building. I think it’s got to be all mental. There are going to be times where they make runs and their crowd may get involved in the game and it may get loud in there. But we have to make sure we have to keep our composure and just keep going, keep attacking.”
While their 24-17 regular season home record was tied with Miami and Chicago as worst among the 16 playoff teams, the playoffs have been a different story.
The Celtics won six of their first seven at the Garden in the opening three rounds, and went 7-2 at home to advance to the NBA finals . They dropped Game 3, 91-84 to the Lakers but came back to win Games 4 and 5 to finish 9-3 at home in the playoffs.
While it was not the 13-1 mark they had on the parquet in their 2008 title run, the energy in TD Garden the last two games clearly helped the Celtics. And they were quick to point that out after the game.
“The energy in the building really feeds our defensive intensity,” Tony Allen  said. “We all feel it.”
Now, the Celtics need to find a way to replace that energy with focus.
“Mental toughness,” Allen added. “Guys staying together and knowing what our goal is and everybody knowing what their role is when we get down there. And I think that’ll get the win.”
Ray Allen  remembered 2008 after Game 5 Sunday night. Those finals ended with a celebration on the parquet. But if the Celtics can win once more, this celebration will be just as sweet.
“That’s the beautiful thing about this whole situation,” Allen said. “The circumstances that have been before us all playoffs long. We never had home court advantage except for the first round. We had to win on the other team’s floor. We talked about what team we’re going to play in the first round. I remember sitting in the locker room and we’re watching Miami and Milwaukee play and we’re talking about where we want to go.
“It seemed like so long ago. At the same time, we had to beat Miami on their home floor, we had to beat everybody on their floor in order for us to advance. We’ve been in this position before. I think the guys mentally are ready for it. We’ll get prepared and get ready to get it done.”