Celtics can't play any worse, can they?

If Boston Celtics fans would like to know what rock bottom looks like, they need not look further than Monday’s Game 2 performance against the Philadelphia 76ers.

The No. 4-seed Celtics’ effort against the eighth-seeded Sixers was insipid, and their play was embarrassing from start to finish. Boston couldn’t shoot, was dominated on the boards and turned the ball over 17 times. The experienced Celtics made uncharacteristic mental mistakes in crunch time.

It was the kind of humiliating all-around offering that couldn’t help but leave one questioning how the Atlantic Division champs possibly defeated Atlanta in the first round to begin with.

But Boston nearly beat Philadelphia anyway. To be completely honest, the Sixers are lucky the Celtics didn’t.

The Sixers escaped TD Garden with an 82-81 victory behind 18 points from Jrue Holiday and 13 points, six rebounds and seven assists from Andre Iguodala, tying their Eastern Conference semifinal series at 1-1 as the teams head to Philly for Game 3 on Wednesday. Through two games, the series has looked as balanced as could be, with each team grinding out a one-point win.

But don’t be fooled into thinking that the even tenor of the matchup is a result of having two evenly matched teams.

Philly’s limited success thus far in this showdown has stemmed almost exclusively from Boston’s utter ineptitude — a level of ineffectiveness that made the jump from being disconcerting in Game 1 to staggering in Game 2 — and maybe that’s why the visiting Sixers basked in their Game 2 win like they did.

They know it’s probably the only one they’re going to get, and it’s becoming abundantly clear that Philly’s best is only marginally better than Boston’s worst. So the Sixers might as well live it up while they still can.

"Our young guys just keep growing, and they’re really becoming men," Sixers coach Doug Collins said of his team’s mettle down the stretch, naming nearly every player in his rotation as he beamed like a proud father. "All season long, we couldn’t win these games, and now our guys are believing they can do it, and it is pretty special to watch."

Collins spoke of his team like they were an overmatched, ragtag, happy-to-be-there group of overachievers because that’s exactly what they are. To their credit, Philly is under no false impression that one loss has put the big bad Celtics back on their heels.

That’s the way the Sixers have to think if they want to have a chance at hanging around against a veteran Boston team that’s now very ticked off.

“I don’t think the Celtics have any doubt,” Collins said. “The one thing about this franchise, it’s always been a very confident franchise. They’ve always felt they were going to win. … I don’t see us denting their confidence.”

Early Monday, the Celtics had every reason to be boastful, taking an early 9-0 lead to start the game. Boston shot 11 of 22 in the first quarter and led 25-21 after one, but the next two periods were absolute stinkers. The Celtics shot 5 of 20 from the field and scored just 13 points in the second, then followed it up with a 4-of-17, 11-point performance in the third.

Philly, which managed just 15 points itself in the second quarter, took a 49-47 lead on Lou Williams’ tip-in with 3:08 left in the third and eventually expanded the lead to as many as 10 before settling on a 57-49 advantage heading into the final period.

Boston turned things around in the fourth, scoring 32 points on 13-of-20 shooting while knocking down 6 of 7 3-point attempts. But the offensive outburst came far too late, Kevin Garnett got whistled for his third moving screen of the night with the Celtics down three with 10 seconds left — a call that was correct, despite its unpopularity among the angry mob of 18,000 that encircled the court — and the Sixers held on for the victory.

“We put ourselves in that position at the end of the day,” Celtics coach Doc Rivers said, but only after admonishing the referees’ call, accusing them of picking on his star big man. “I say all the time, if you put yourself in a position to let someone else do something, you can lose games, and that’s what happened.”

And that’s just it. Philly didn’t so much win Monday’s game as much as Boston lost it.

It would be an alarming overstatement to say that the Sixers hit the Celtics in the mouth with their sneaky road victory. But if nothing else, the Sixers put up enough of a fight to suggest that if they go down in this series — or, rather, when they go down — they’re going to do so swinging.

Philadelphia survived the first round and advanced to this point by offing a beat-up Bulls team that, somehow, managed to play worse than it did. That's been the case in Round 2 as well. For Philly, the only difference this time is that Boston, unlike Chicago, still has a full complement of players at its disposal — old and dinged up as they may be — and they’ve got years of championship pedigree to fall back on.

The Celtics know they’re better than this — something the Bulls couldn’t be quite so sure of with stars Derrick Rose and Joakim Noah sidelined — and they’re confident it’s just a matter of time before they sort things out and continue on their war path toward a conference finals matchup with Miami.

"It’s the playoffs; it’s up and it’s down," said Rajon Rondo, who recorded more than 10 assists for the 29th time in 30 games, handing out 13 dimes in the loss. "You’re not going to win 16 straight games, so give them credit. They are not a pushover team."

So, congratulations, Philly. You’re not a pushover. But you also still don’t have a chance.

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