The Hawks promise things will be different.

They have no choice. The alternative means a likely end to their postseason.

The Hawks have not resembled the team that won 60 regular-season games and earned the No. 1 seed in the Eastern Conference throughout these playoffs. They struggled to defeat the Nets in six games in the first round and find themselves trailing the Wizards 2-1 in the second round. Game 4 is Monday night. Only eight teams in NBA history have come back from a 3-1 deficit in a best-of-seven series.

“Like my dad always tells me, you can’t think you’re the No. 1 seed, you have to act like the No. 1 seed,” DeMarre Carroll said Sunday. “I feel like we didn’t act like we were the No. 1 seed. We haven’t acted this whole series like we are the No. 1 seed. That should change tomorrow. If we are going to go out, we are going to go out swinging.”

The sting of a last-second 103-101 loss in Game 3 was still being felt a day later. The defeat, on a banked buzzer-beater by the Wizards’ Paul Pierce Saturday, put the Hawks in their current hole. A unit of Hawks reserves nearly completed a remarkable comeback from a 21-point fourth-quarter deficit only to receive a punch in the gut.

Now, for the first time this postseason, the Hawks trail a series.

“We understand the importance of Game 4,” Al Horford said. “We are looking forward to it. We wish we could play today.”

The Hawks held a light practice on the campus of George Washington University Sunday after a lengthy film session. They needed time to dissect what went so wrong in the Game 3 loss that was out of hand before Mike Budenholzer appeared to raise the white flag. The coach put in a group of reserves for the final eight minutes. The unit nearly won, especially after Mike Muscala drained a game-tying 3-pointer with 14.1 seconds left.

The starters gave credit to their teammates but vowed not to come out with a lack of intensity in Game 4. The Hawks’ only leads were 2-0 and 4-3 before the Wizards eventually built a double-digit lead they held until the final rally.

“We won’t have another effort like that, rest assured,” Carroll said. “I don’t think we had a sense of urgency as a starting group. We came out and the first five possessions, we chucked up 3s instead of attacking them and putting them on their heels. We watched film today and we understand what we need to do coming out next game. If you are on the Atlanta Hawks and you don’t come out with a sense of urgency next game, then you are not an Atlanta Hawk.”

One of the issues facing the Hawks in Game 3 was an illness to Paul Millsap. The forward did not start the game as he dealt with flu-like symptoms. By the time he entered the game, less than five minutes into the first quarter, the Hawks trailed by seven points. Budenholzer said he did not believe Millsap’s early absence contributed to the Wizards’ fast start with a physical charge that put the Hawks in an early hole.

“We all know that Paul can give us a lot and he will give us a lot,” Budenholzer said. “Judging on how we all played (Saturday), I’m not sure him starting or him coming off the bench, we all weren’t where we needed to be or wanted to be. I don’t think it would have made any difference starting him or bringing him off the bench.”

The Hawks made successful drives to the basket in the second half of Game 3. It will be a point of emphasis in Game 4. Jeff Teague had 11 of his 18 points in the second half and Dennis Schroder had all 18 of his points in the second half, 16 in the fourth quarter in leading the late charge. The point guards are responsible for getting the offense on track. Teague said the offense has been slowed for much of the series.

“We’ve just got to drive the ball,” Teague said. “They gave us a lot of open lanes to get to the rim. Last night, in the second half, me and Dennis started doing that. It opened up the floor for us. We were trying to force motion (offense) and all we had to do was drive the ball. There were so many open lanes but we were trying to force it. It was making our offense really stagnant. We’ve got to drive the ball.”

Time may be running out for the Hawks to return to the style of play that made them so successful.