BOSTON - Oh, what could have been.

Throughout the seven-game series between the 76ers and Boston Celtics, offensive efficiency was scarce and scoring was almost an afterthought.

Though scratching and clawing to the final buzzer Saturday night at TD Garden, the Sixers' improbable run through the playoffs came to an end with an 85-75 loss to the Celtics, who will now face the Miami Heat in the Eastern Conference finals starting Monday in Miami.

Boston's Rajon Rondo hit two long jumpers after Paul Pierce fouled out with 4 minutes, 16 seconds left for the final blows that effectively ended the Sixers' hopes.

"Nobody is hanging their heads here," said guard Lou Williams. "We were making a run [when Pierce fouled out], but if you would have told me that Rondo was going to make [two long jumpers] to seal the game for them I probably wouldn't have thought that was going to happen. That's not usually his game. Those aren't shots that he normally takes, and for him to make them was a huge credit for him. We have to be happy with the way we fought."

Sixers coach Doug Collins agreed. "When the game was in the balance they came up with the plays," said Collins. "Rondo made huge plays to break the game open. I thought if we could score 85 we could win. But our inability to score plagued us throughout the season. It looked like the game was getting away from us, but we were right there. I thought turnovers hurt us early in the game. We did a good job of weathering things. They hit us in the mouth early, but we came back."

Trailing by 53-45 in the third quarter, the Sixers used a 7-0 run to get to within 53-52, keyed by two fabulous plays by guard Jrue Holiday. First, Holiday snuck behind Kevin Garnett after the center had corralled a defensive rebound, poked the ball away, and made an acrobatic layup. He then made a steal at the other end and fed Andre Iguodala for a dunk and a one-point deficit.

Holiday got himself yet another steal on the Celtics' ensuing possession and again fed Iguodala, who was streaking down the court. Iguodala got fouled on his drive. With a chance to give the team its first lead in the second half, he missed both. From there the Celtics used a 9-3 run and were able to hold off the Sixers.

Ray Allen, who was struggling mightily from the floor for most of the series and continued his cold spell on Saturday, was able to hit two huge, season-saving shots for the Celtics in the fourth quarter.

With the Sixers creeping to within three at 57-54, Allen (11 points) drained a patented three-pointer to give the Celtics a six-point advantage with 9:51 left. Four minutes later, when the Sixers were within five at 66-61, Allen drilled another for a 69-61 lead.

The Sixers' plan of not worrying so much about Allen late in this series, even leaving him at times to double-team the likes of Pierce (15 points) and Garnett (18 points, 13 rebounds), was working well. It was a gamble, and one that Boston coach Doc Rivers didn't mind seeing.

"They were kind of letting him get shots," Rivers said about the previous games.

He did, but the Sixers continued to linger, and when Pierce fouled out as the Celtics hung on to a three-point lead, a trip to Miami seemed more than a small possibility. But Rondo scored 11 points after Pierce was disqualified, including a long three-pointer that gave Boston a 78-68 lead wiht 2:09 left.

"My night wasn't going well. I figured, 'Stay positive,' " Rondo said.

Rondo had 18 points, 10 rebounds, and 10 assists. Brandon Bass added 16 points.

The start was exactly what Collins didn't want, as he stressed the need for his young team to see the ball go in the basket early. That didn't happen as the Sixers missed nine of their first 10 shots and fell behind by 10-2 before Collins was forced to call a timeout less than four minutes into the game.

Whatever was planned worked better as the Sixers were able to forge ahead by 20-19 late in the quarter despite shooting 6 for 20 and committing three turnovers. They also seemed to be in a good spot as Rondo was strapped to the bench with a pair of fouls.

The Sixers, though, found no better success at the offensive end in the second quarter, missing 13 of their 18 shots and giving the ball away five more times. The turnovers gave the Celtics run-outs, and uncharacteristically the Sixers were outscored on fastbreak points by 13-2 in the first half.

The Sixers made a big comeback in the third quarter until Iguodala missed those two free throws.

Iguodala scored 18 points, while Elton Brand and Holiday each scored 15 for the Sixers.

And now the offseason, which is sure to be a busy one, begins for Philadelphia.

Contact Bob Cooney at cooneyb@phillynews.com.