It would be easy to dismiss the Sixers' win Monday night over the Boston Celtics as a classic NBA "human nature" result, if only because postseason outcomes like this one have happened approximately a zillion times before.

That's not the exact analytics of the thing, because quantifying emotion and motivation isn't easily done with a calculator. But it is close enough, when you have one team with a 3-0 series lead and another needing to save face in front of its home crowd.

Reasonable observers of the series would still conclude that the Celtics are going to emerge the eventual winners, and that the Sixers won't be able to turn Monday's victory into the start of a four-game streak.

Still, what the Sixers earned for at least two days is the right to feel good about themselves, and they deserve it because the flip side of human nature is that NBA players know when they are fighting a lost cause and it often shows. For these Sixers, the desire to not go quietly into the playoff night was stronger than the daunting mathematics of their situation.

That's why Brett Brown said his main job in preparing the team for this game had less to do with the X's and O's of the matchup than with the mental outlook of his team.

"I have to do a good job coaching their spirit as much as the game," Brown said just before tipoff. "All of us have a breaking point [where] your spirit isn't as strong as it needs to be. That has to start with me … the body language, the messaging. I'm good to go."

In order to get the energy he thought the team needed, Brown made T.J. McConnell good to go from the start as well. He dictated an aggressive defense predicated on double-team traps designed to force turnovers and make the Celtics uncomfortable. The danger would have been if Boston passed effectively out of the pressure, found the open man,  and buried its three-point shots. On this night, the Celts didn't. Of course, maybe that was human nature on their part, too.

"We needed to come in with a spirit and a tenacity that T.J. epitomizes. We were fighting for our lives," Brown said. "You can't do it all with mind-set. You need an aggressive defensive format. It equals something of a risk/reward that they split the trap or pass out of it and play four-on-three. But we felt it [was] a risk we had to take to get the reward they got."

Boston didn't make them pay – dropping in just 11 of 32 on three-point shooting – and coach Brad Stevens thought his team settled for too many so-so shots, particularly in the first half. Additionally, the Sixers harassed the Celtics into 15 turnovers and also won the battle for offensive rebounds decisively. Put it together and the Sixers had 19 more shot attempts from the field and, on a night when neither team was terribly accurate, that was more than enough to swing the outcome.

"We were ready to play, but Philly played better and was the more physical of the two teams out there," Stevens said. "They just beat us."

It was a formula that worked fine on Monday before a crowd that grew in both numbers and enthusiasm as the game wore on. The early start on a weekday made it difficult for all the fans to arrive on time, but when the game shifted to the Sixers in the second half, they were all there and apparent.

The trick will be to carry over the energy and spirit to TD Garden on Wednesday night in Game 5. The unfortunate lesson of NBA history is that is usually a different story. The Celtics will have their own human nature on the line before their own fans that night, and settling for shots or being the second-most physical team on the court won't be as easy to shrug off.

The Sixers deserve credit for what they did on Monday night. A lot of teams would have barely made it to the arena, but there is a residual effect from the recent years of losing that keeps this team from packing it in, even if few of the players went through the dismal days.

"That's the most difficult thing in this league, when you're not having success, is maintaining the joy and the desire to continue to work for yourself and the team, and nobody has done it better than Brett," Stevens said. "Everybody 'loves' basketball, but that's tested in an 82-game season and really tested when you're not having success. They way they have created a culture in which they find joy is special."

Success eluded them in this series until Monday night, and maybe this result was only a mirage. But for the next two days, their human nature is what got them through to play again.