There never should have been any doubt, really.
And for the most part, he was right. But in Sunday's Game 7 against Cleveland, when everything the Celtics had accomplished since November was in jeopardy, Boston's fate rested squarely on Pierce's shoulders.
As great a shooter as Allen can be, he was off the entire series against the Cavs and spent most of the fourth quarter on the bench. And even when at his best, he's more of a complementary offensive player, a catch-and-shoot guy.
As for Garnett, he might have been Boston's MVP candidate, but he's not a player who takes over a game offensively. ESPN's chat between him and Bill Russell was perfect because the players share many traits, especially unselfishness, outside of Russell's 11 championships.
Boston's take-over-the-game player is, definitively, Paul Pierce. Just ask Garnett:
"Tonight was basically get the ball to Paul Pierce, get the hell out the way," the All-Star said after the game.
And despite LeBron James' best game of the series, a 45-point effort, Pierce matched "The King" shot for shot to score his 41.
Pierce's effort was all the more impressive because he didn't touch the ball on some Boston possessions. James, on the other hand, dictated Cleveland's attack every time down the court — he had to — and played all but a minute of the 48.
The great thing about watching Pierce excel is that nothing he does is spectacular. Unlike the behemoth James, Pierce doesn't jump out of an arena, doesn't glide through the air — at least not in his 10th season out of Kansas.
Rather, Pierce, when at his best, uses his body smartly to create shots for himself and also get to the foul line. On Sunday, James, who is 6-foot-8, had two inches on the guy he was guarding, but Pierce was able to create enough space to make 13 of 23 field goals and 11 of 12 free throws.
And he hit one big shot after another.
As did James, but we all knew that Boston is the better all-around team. The only chance Cleveland had to escape with the road victory was if James outplayed every Celtic. Take away three of Pierce's field goals, and Boston's 97-92 win could have gone the other way.
But despite having to guard James for most of his 44 minutes, Pierce never fatigued, never let up, and he made one of the biggest non-box score plays with just less than a minute to play.
Boston was clinging to a 91-88 advantage, and Cleveland's 7-3 Zydrunas Ilgauskas was prepared to win a jump ball against Boston's 6-8 James Posey. The smart play for Ilgauskas was to tap the ball toward James, who should have been able to box out Pierce.
Pierce, however, wasn't giving in to the bigger, stronger James. Instead, as the ball was tossed into the air, he bulled his way past James toward where he anticipated Ilgauskas would direct the ball. And sure enough, there was the orange sphere, just within Pierce's wingspan. He tipped it to himself, corralled it as he fell to the floor and quickly called timeout.
The play didn't result in any Boston points, but it ran off a valuable 20-plus seconds that Cleveland could have used at the end.
Garnett is the Celtic best known for his hustle plays, but Pierce made the defining play, the effort that will be highlighted decades from now on those NBA Films shows.
"His mental toughness was fantastic," Pierce's coach Doc Rivers said. "Obviously he was great offensively. I was just happy.
"Paul had two turnovers (toward the end). When you have those turnovers down the stretch, you can easily go the other way. ... I thought he got better after that, so I was very happy for him."
Of course, Cleveland's elimination shouldn't take away from James' performance. If he had Pierce's teammates, there's a very good chance he'd be back in the Eastern Conference finals against the Pistons.
He attacked the Celtics from the opening tip, making sure the game never slipped away from the Cavs. Whenever it appeared Boston was ready to build an insurmountable lead, James made a huge basket or created one for Cleveland's only other offensive player Sunday, Delonte West.
But at the end, it was James who let Pierce get to the jump ball. And it was James who took a poor, driving, in-between shot that missed badly with the Cavs trailing by three. On his way toward the basket, James passed on taking an open 3-pointer, which begs the question, 'How much confidence does he have in the long-range shot?'"
(James finished 3-of-11 from behind the arc.)
James should be given credit for taking ownership of his team. He never shied away from the spotlight, putting the Cavs on his back.
But at the end of the day, James was left to talk about the opposing player who's moving on to the next round.
"When a guy keeps hitting jumper after jumper, you have to respect that," James said.