ATLANTA — It’s nights like these that Kelly Olynyk really proves his worth to the Celtics. They may not come as often as the organization would prefer, yet Olynyk tantalizes his team with such performances because the Celtics are a better team when he flourishes offensively.

He scored 26 points in the Friday win over the Atlanta Hawks, but his exploits were overshadowed by another heroic fourth-quarter performance by Isaiah Thomas. Olynyk’s production was just as critical to the team’s victory, however. He was able to not only knock down 3-pointers, he scored five of his nine field goals at the rim, which hasn’t been his strength.

The Celtics are a better and more potent offensive team with Olynyk stretching the floor, and the Hawks featured a defense Friday that Boston could potentially see in the playoffs. Atlanta doubled Tho­mas in the first half, limiting him to 7 points and seven shots.

Olynyk was the wide-open beneficiary of that double and he scored 18 points in the first half on 7-for-9 shooting, forcing the Hawks out of their double team. It was the Olynyk Affect, the exact type of floor-stretching offense that burns defenses with 3-point shots or opens the middle for Thomas drives.

“I wouldn’t say they were blatantly leaving me [open], I would say they were trying to help on other guys, help on IT’s drives,’’ Olynyk said. “[In] other games people don’t help, he has 52 [points]. So you’ve got to do something. It was good that we could step up and make some shots and take a little pressure off him.’’

Olynyk’s importance to the Celtics’ long-term success is unquestioned. There was a reason why the Cleveland Cavaliers acquired Kyle Korver from the Hawks, for the express purpose of stretching the floor. And the Hawks wanted often-traveled veteran Mike Dunleavy to do the same, and he responded with a pair of threes in his Atlanta debut, sparking the Hawks’ late rally.

Shooters are at a premium in the NBA, and the Celtics drafted Olynyk four years ago to shoot threes. But he has been beset with injuries and inconsistency. The Celtics were dispatched by the Hawks in six games last season in the playoffs and Olynyk was limited to 32 minutes in that series because of a right shoulder injury that required surgery.

What if Olynyk had been healthy in that series? Would the Celtics have been more competitive with another shooter? The Celtics were putrid from the 3-point line in that series (27.5 percent).

Olynyk laments missing that series.

“It’s tough because [the Hawks] obviously play the same way they play in the playoffs last year, really crowd the paint, really help oriented, you’re not going to drive by a guy and lay it in against them,’’ Olynyk said. “Their team defense is too good, too connected. So they force you to kick the ball out and make 3-point shots or made deep shots with the late contest, so you need shooters to be able to do that and I thought I could really help our team last year against them. I had some good games against them in the regular season.’’

After a tough December in which he shot just 30.8 percent from the 3-point line and averaged 6.5 points, Olynyk has responded in January, averaging 11.7 points and making 47.6 percent of his 3-point attempts (10 for 21). In the 12 games Olynyk has scored in double figures this season, the Celtics are 10-2.

“That’s big for us,’’ small forward Jae Crowder said of Olynyk’s production. “For him to step up and make shots and opp­osing teams trying to take away the shots and get a switch, he’s able to bury the switch and get a bucket. That’s like playoff-type basketball. That’s what we need him to do for us, especially when he’s making shots. He’s got to be able to roll and switch and get a bucket or be a passer.’’

And the 25-year-old Olynyk has surprisingly become a solid defender as well as an improved playmaker. Against the Hawks, Olynyk provided resistance to All-Star Paul Millsap and was able to get into position to draw charges and challenge shots. Olynyk still picks up his share of fouls because of shaky decisions, but he said he’s worked on improving himself.

“It’s tough, you’re not going to get the benefit of the doubt a lot of the time but you’ve got to know what was the right defensive play and the wrong defensive play,’’ he said. “And our coaching staff has been helping me, showing me film after ­every game of my defense and where I was in the right spot and how I can get better and that’s huge, just reaffirming in your mind, they called [the foul] but that’s what we wanted to do. You were in good position but you got a bad whistle.’’

After missing the first six games of the season following that shoulder surgery and taking a full six weeks to work himself into form, Olynyk is finally starting to contribute and become a more consistent factor, which is exactly what the Celtics need. There are going to be nights where he replaces Amir Johnson at center — such as Friday — when opposing teams go small and the Celtics want to counter with skill. With the second half of the season about to begin, it’s heartening for the Celtics to have an engaged and productive Olynyk and he under­stands his importance to their success.

“I think [confidence] is contagious,’’ he said. “I think I can really help this team on both ends of the floor. I’ve just got to be ready to come and bring it ­every night and do whatever I can to make this team better.’’

Gary Washburn can be reached at gwashburn@globe.com.