CHICAGO -- Celtics coach Doc Rivers often dumbs down basketball to its most simplest form when detailing why his team wins or losses a game.

"It’s a make/miss league, and it always will be," said River, echoing a familiar sentiment after the Chicago Bulls emerged with an 89-80 triumph Thursday evening at the United Center.

Rivers said Thursday's tilt came down to who made their shots down the stretch and, while Boston couldn't buy a bucket at times, the Bulls did enough to emerge with the win.

"It was a strange game, I thought we got a lot of great shots, but we couldn’t make anything," said Rivers. "We got Ray [Allen] wide-open shots, Paul [Pierce] had wide-open shots, and Kevin [Garnett] had wide-open shots. Maybe it's a factor of playing [Wednesday] night, but I told them at halftime that I wasn’t upset at our shots. I just wish some of them would go in. But they didn’t.

"I was proud of our guys, I thought we fought back into the game, got a lead, [but] then they went on another run, and it’s tough when you get down like that and you have to fight your way back. It’s funny, [Wednesday] we were horrendous [in a loss to the Pistons]. [On Thursday], I thought overall, it was two great defensive teams and it came down to make/miss at the end of the game, if you want to simplify it."

Here's proof: Pierce made his first three shots Thursday, but connected on just three of his next 13 while finishing with 14 points. Allen missed his first seven attempts, but made four of the next six, including a trio of 3-pointers to aid the rally with 12 points overall.

Even still, the Celtics really labored to generate points, particularly as the Bulls dominated the glass at both ends of the floor (52-37 overall advantage, with the Bulls grabbing 16 offensive rebounds). Chicago didn't always cash in on its second-chance opportunities (3-for-13, 12 points), but it was still enough to prevent Boston from getting in transition and generating the easy points it got during Sunday's win over the Bulls at TD Garden.

Rivers thought the missed shots leaned uncharacteristically heavy on his team Thursday.

"I thought [the Bulls'] defense was good, too," said Rivers. "But I thought we missed shots. I told our guys at halftime, we dont’ show it often, but I thought the missed shots affected our energy. You could literally see it; it was visible to me. That's unusual for us. Usually when people are scoring on us, that affects us. But when we miss shots, it usually doesn’t bother us at all. And I thought a lot of the guys got frustrated with the shots they missed."

While the Celtics (31 of 78, 39.7 percent) couldn't get their shots to fall, the Bulls (30 of 76, 39.5 percent) got some back-breakers to drop, like Taj Gibson picking a loose ball off the ground and floating in a bucket in the final frame, or Luol Deng making one of six killer 3-pointers, even as Boston made a strong effort to close out on him. What's more, the Bulls always seemed to be scoring at the end of the shot clock.

But, in the end, it came down to those makes and misses.

"I thought we had some great shots, they just didn’t fall," said Pierce. "I had a couple looks that I normally knock down; I know Ray had some good opportunities, and [Rajon] Rondo the same. Then you come back and play defense for 22 or 23 seconds, and you don’t get the rebound. It saps the energy."