BOSTON - The 76ers needed to beat a lot of things on Wednesday night: the explosive energy inside a sold-out TD Garden, the emotional impact of their embarrassing loss the night before, and, of course, the Boston Celtics themselves.

While the Celtics hadn't lost since last month, the Sixers were only one day removed from an epically bad defeat to the Chicago Bulls.

Related stories

And yet as the game wore on, it was difficult to tell which was the better team. Back and forth went the game - and the score.

But at crunch time, the Celtics proved why they've now won 14 games in a row, topping the Sixers, 84-80.

The Sixers dropped to 11-18. The Celtics, led by Ray Allen's 22 points, improved to 23-4.

The Sixers had their chances: Andre Iguodala missed on a drive with 14.9 seconds left that could have tied the game. Iguodala looked astonished at the lack of a whistle.

"We got our best player the ball on the elbow and he got a step and got in the lane, and then after that I really couldn't see what happened," Sixers coach Doug Collins said.

Allen made two free throws with 5.6 seconds left to effectively end the game.

"It's pointless at this point; we're not trying to go back," said Iguodala of the no-call. "It wasn't called, whether it was a foul or not."

Iguodala made 2 of 11 shots and finished with nine points.

"That's part of the team's defensive scheme is to keep me out of the paint, so [we're] trying to make good reads and trying to play off of that and take what the defense gives you," said Iguodala, explaining his offensive mind-set.

With 4 minutes, 49 seconds left in the game, the Sixers were ahead, 74-70.

"We're working on" closing games, said power forward Elton Brand, who finished with 16 points and 12 rebounds. "A few games, we've been closing well. . . . We've been improving in that aspect, but you look at their team - it was like clockwork: free-throw line, free-throw line, made bucket, made bucket."

In the fourth quarter, the Celtics were 12 for 14 from the free-throw line. The Sixers were 1 for 2.

"My concern coming in is always: Can we score?" Collins said.

Only 24 hours before Wednesday's game, the Sixers trailed by as many as 51 points in a 121-76 loss at the Bulls, a game that made some question exactly how much the Sixers had improved in the previous three weeks.

Suddenly, the Sixers' 8-3 record during an 11-game stretch was cast in a different light.

Is this team any good?

"That's more what our team is like," Brand said after Wednesday's improved effort. "I know that the Bulls aren't 45 points better than the Celtics. And that's what we lost by. It's disappointing we didn't come with it [on Tuesday], and it's disappointing we didn't close it out here."

Standing outside his team's locker room, Collins seemed reassured that the complete meltdown against the Bulls was an aberration.

"They showed me who they are, and I knew that, I knew our guys were going to compete like this," Collins said.

Read The Inquirer's 76ers blog, "Deep Sixer," by Kate Fagan at http://go.philly.com/dsixEndText

Contact staff writer Kate Fagan at 856-779-3844 or kfagan@phillynews.com.