And they still found themselves fighting tooth and nail for the final 12 minutes of Game 2 at the Staples Center.
Allen made seven 3-pointers in the first half, breaking the record previously held by Michael Jordan for the most 3s in one half of a Finals game. He had 27 points at the break and finished with eight 3-pointers overall, breaking a Finals record he had once shared with Kenny Smith and Scottie Pippen. When the dust had settled, he had 32 points on 11-of-20 shooting, 8-of-11 from downtown.
And yet the Celtics still trailed 90-87 with just over five minutes remaining in Game 2, and it took an 11-0 run over the next four minutes to hold the Lakers off and win their first game, a 103-94 final.
"We needed every one of them, I can tell you that," coach Doc Rivers said of the Allen 3-pointers. "It's amazing, when you think about it, that we had a player score 27 points in the first half and we were only up six. That tells you how close this series is going to be."
The first time Allen hit a 3, it was midway through the first quarter. Andrew Bynum had put the Lakers out in front with three early buckets, and it took a deep drain from Allen at the 6:47 mark to tie the game, 11-11. Then Pau Gasol scored, and Allen hit another 3 to put the Celtics up one.
Then came the second quarter. And from the 9:37 mark, straight through to halftime, every single field goal the Celtics hit was a 3-pointer from Allen. No one else could get a shot in.
"He saved us in that first half," Rivers said. "With Kevin [Garnett] in foul trouble and Paul [Pierce] struggling a little bit, we needed points. Ray gave them to us."
"I can't say enough about what Ray did for us tonight, especially in the first half," Rondo said. "He carried us the whole way. Guys were in foul trouble — from Kevin, to [Kendrick Perkins], just everyone. We were playing on our edge, but Ray, he held us through it. He got us through the first half and took over the game. For me personally, it was fun to watch. I just tried to get him the ball on time and on target when he needed it."
It wasn't until the final minute of the half, when he launched one from the corner that just barely rimmed out, that he finally missed one. It evoked memories of Jordan, the MVP of the 1992 Finals against the Blazers, knocking down six 3s in the first half of Game 1.
Memories that for Allen, back then a junior in high school, were still fresh.
"I do remember," Allen said. "He had it going. I think as a child, those are some of my favorite memories, just being a fan of MJ and the things he did in the playoffs and in the Finals. That's something that's going to stand out in my mind for the rest of my life. I know we have a great challenge as players now to imprint these good things on kids growing up in the world. So I'm glad that we're able to do this."
It was such a great accomplishment for Allen, such a great moment in the 14-year career of the future Hall of Famer, that the Celtics had a special sense of urgency to finish off the win.
They eventually did. By forcing a few Laker turnovers late and hitting their shots down the stretch, the Celtics were able to walk out of the Staples Center with a nine-point win.
"There's no better place, moment, time to play a game and to win a game," said Allen. "To win it in great fashion, where everybody has to do it together as a team. And to be able to shoot the ball — I don't even know what record it is that people are telling me I got, but it's great to have. It's great to be able to look back on this and say I did that. So this is definitely the time. This is definitely our time."
June is when Boston's basketball heroes are made and they're now three wins away from making history.