When the season began, Oklahoma City coach Scott Brooks had a simple goal for his team: He wanted them to play meaningful games in March and April. March is over, April is upon us and his team is 46-28 and a lock for the playoffs. At this rate, the Thunder might be playing meaningful games into May.

“I don’t know if surprised is the right word, but I like what we’re doing,” Brooks said before his team won another important game over the Celtics Wednesday night at the TD Garden. “I like where we are but we still have a lot of work ahead of us. We don’t want to just stay at this level. We want to keep getting better.” 

It doesn’t really work this way. Oh sure, the NBA would love it if all of its young teams were built through the draft and allowed to grow and achieve success together the way the Thunder have, but the success-to-failure rate for this particular blueprint is remarkably low.

Draft picks don’t always pan out. Ego, money and status have been known to throw a wrench into even the best laid-plans. Then there is that crucial moment when a franchise has to decide whether to spend that well-appointed cap space on a veteran that will either get them over the top or wreck their delicate balance.

The Thunder haven’t reached that last point yet, and even if they did there’s no guarantee that 33-year-old general manger Sam Presti will tempt fate by conforming to traditional NBA wisdom. Why should the Concord, Mass., native start now?

“I don’t look at our guys as being young,” Brooks said. “I know they are. I’m not a dummy. I look at them as NBA players. If they put their name in the draft and we draft them they have to be treated like NBA players, like men. Regardless of how young they are, we have a demand that they have to have that level every night. Effort and being committed to playing winning basketball has nothing to do with age.”

In Kevin Durant, Presti not only has that rarest of commodities — a true superstar — he also has what may very well be a perfect team leader. The Thunder may not need that veteran presence to teach them how to win, because they’re doing a fine job of figuring it out for themselves.

“They’re coachable and they allow myself and our staff to really push them and challenge them,” Brooks said. “And they challenge each other. They’ve made a winning environment.”

Before Wednesday’s game, the Celtics were the only team that Durant did not have a win against in his short career. (Make that Durant and Jeff Green.) The Thunder are almost maniacal about reminding everyone that Green is just as important to their success, along with second-year point guard Russell Westbrook.   

Durant never lets anyone forget, either. He constantly praises his teammates, never allowing any individual accolades go without mention their contributions. It’s so pure and appears so genuine that even the hardened NBA cynic can’t roll their eyes at the kumbaya vibe that emanates from their locker room. 

On Wednesday, Durant was sensational against the Celtics, scoring 37 points and making all 15 of his free throws. That he took two less free throws than the entire Celtics team prompted Kevin Garnett to say, “I thought we were playing Michael [expletive] Jordan the way he was getting the whistle.”

Maybe, but he got those 37 honestly. He also took 20 shots from the field and made 10 of them and it seemed surprising that he somehow missed that many.

The Celtics started the game with Ray Allen covering Durant, and almost dared him to try to win it by himself. Boston coach Doc Rivers seemed fine with that strategy, noting before the game that Durant scored 36 points the last time the two teams played and the Celtics still won. Still, Rivers knew that he was playing with fire. He compared Durant to a cross between Dirk Nowitzki and George Gervin, but noted, “Neither one can handle the ball like Durant.”

Late in the game, Rivers switched Paul Pierce to Durant and had his big men hedge off screens to try to bump him off balance. “It was a bitch, honestly,” Rasheed Wallace said.

That was when Green got free for two huge 3-pointers in the final minutes that iced the game. Can’t have one without the other, after all.

“Jeff Green is a big shotmaker,” said Rivers, who knows that all too well after watching him at Georgetown while his son, Jeremiah, was a Hoya. Westbrook also was great with 21 points and 10 assists, and then there is rookie James Harden, who Rivers likened to a mini-version of Pierce. 

But really, this all comes back to Durant. Much was made of his defensive shortcomings before the season, but he has improved greatly on that end, and the proof is in the Thunder’s defensive numbers.

They are fourth in opponents’ field goal percentage, third in defending the 3-point line and sixth in defensive rating (a stat that estimates points per 100 possessions and is adjusted for pace). That’s up from 27th, 13th and 20th respectively from last season.

There are many reasons for that success, not the least of which has been the contributions of assistant Ron Adams, the Thunder’s version of Tom Thibodeau, but Durant’s improvement is a major factor.

“We’re not a good defensive team without having him out there and he understands that,” Brooks said. “He’s a young player in this league, but guys respect him because of the work that he puts in and he does it on both ends. It’s hard to gain your team’s respect if you’re just looking to score and get numbers. That’s not what he’s about it and guys see that.”

The ultimate test will come in the playoffs. Maybe they will be good enough to steal a round and keep playing deep into the postseason. Maybe this is just the first step on a long journey. It’s all there waiting for the Thunder and Durant and they don’t seem to content to wait their turn.