SAN FRANCISCO — No doubt Brad Stevens had a talk with Isaiah Thomas before, during or after the Celtics’ flight here yesterday. With the Warriors waiting across the bay in Oakland tonight, it’s best to have as clear a head as possible.

While Stevens said, “I’m not worried about anything other than getting better,” he has to be a tad concerned by Thomas’ critical comments — borne of frustration or not — after Monday’s collapse against the Clippers in Los Angeles. It was the second time this season Thomas has publicly questioned strategy, wondering after a home loss to Golden State in November whether the coaches had given up on the game too soon.

Looking at the larger picture now as the Celtics head down the regular-season stretch, Stevens was very direct in remarks to the Herald, questioning the validity of the Celtics’ 40-24 record. The All-Star point guard, on the other hand, seemed to point clearly to the lineups the coach employed in the latest loss, but he was likely more upset that, after building a 13-point lead, he was taken out with the Celts up six in the third quarter and re-inserted with the club down eight in the fourth.

“I’m not concerned,” he told reporters later. “It’s just the way we lost tonight was unacceptable. We lost the game in the last 15 minutes of the game. We played a really good game up until the last 15 minutes, and that’s the players’ fault, the coaches’ fault. That’s everybody in this locker room’s fault. We could have done a lot better.”

Asked what had him so frustrated, Thomas said, “Everything. We should have won this game. We should have won (Sunday in Phoenix). We can’t be experimenting in Game 63.”

About whether he expressed his desire to get back into the game sooner to Stevens, he said, “For the most part I try to let him coach. He’s a very smart dude, and he does a good job of the substitution patterns. But, like, tonight I didn’t say anything to him. Maybe I should have, but it is what it is. We’ll figure it out.”

Thomas’ statements aside, the fact is the Celtics squandered a game to the Suns in which he missed a late free throw and fumbled an inbound pass, leading to the winning bucket. Then they fell hard when the Clippers hit them with a second-half run.

It should also be noted they played both without Al Horford (sprained right elbow). So the key would be not overreacting, right?

“Well, we’ll see,” Stevens told the Herald. “We’ll see. I’ve said all along that we’re not as good as our record. And until we play with better poise and we play with better purpose all the way through, then we’ll have nights like that (against the Clippers). Obviously you can play really well and lose that game, and, you know, I thought we played really well for a lot of the game. And then Jamal Crawford gets hot. That happens in the NBA.

“We have a 13-point lead in the third, and we just didn’t respond when Crawford went nuts. And we had that one other time this year, against one other team, and that’s Toronto, where I felt like we didn’t respond when (DeMar) DeRozan started going nuts. So we just have to get better.

“I think we’re in really good shape, but I also think that we have to improve. And I also recognize that we’re in a tough stretch. We’ve got a lot of road games here in a cluster, from early February to now, and we need to just stay the course, keep our eyes ahead and not get too high or too low.”

But, apologies to Bill Parcells, Stevens simply does not believe the Celtics are who their record says they are. The standings have them second in the Eastern Conference, just three games behind Cleveland. The coach, however, sees beyond the numbers out front. There are factors that have added a little air to the mark.

“I think the biggest thing is we’re 28-14 in close games,” Stevens said. “Usually you don’t have quite that discrepancy.

“We’ve been fortunate. We have to get better. I think that everybody talks about chasing other teams or whatever the case may be. We have a long way to be what I think is competitive at a necessary level to be really good when it’s all on the line.”

Late Monday in his postgame press conference, Stevens dismissed talk of what the loss means in the race with the Cavaliers.

“We’re trying to be the best version of ourselves,” he said. “I don’t care about any other team in the East or anything else. We’re not chasing people. We’re trying to be the best we can be, and if you do that enough times, then you have a chance to play beyond. But we’re not at that level yet. That’s pretty clear. We just need to keep getting better.”

And part of getting better entails dealing with adversity better — both in deed and word.