Taj Gibson said the Knicks got complacent. That was his best explanation after Friday’s horrific 115-99 preseason loss to the woeful Wizards in the first preseason game at the Garden.

The Knicks had pummeled the same Wizards’ club Monday, but four days later were ransacked during a 41-17 second period. They allowed Washington to make 19 3-pointers — most of them wide open. Gibson said the defeat “humbled” the Knicks.

“Everyone’s patting your back and telling you how good you are after the first preseason game,’’ said Gibson, a Brooklyn product. “We relaxed. That’s the way we’re not trying to be. We know the odds are stacked up against us as it is.”

Now it’s four long days off to mull disappointing a sellout crowd at the Garden. The Knicks will finish their preseason with home games Wednesday vs. Atlanta and Friday in the Zion Williamson Show against the Pelicans.

“We’re a talented offensive team,’’ Gibson said. “The offense is not the key right now. We got to get stops. We were flying around [in the first game] but weren’t hungry on defense [Friday]. Our coverages were a little blown up.”

The worst part for president Steve Mills is after the seven free-agent signings and draft selection of RJ Barrett at No. 3, the Knicks’ defense looked indistinguishable from last season’s 17-65 wreckage. But starting power forward Julius Randle, their top signing who committed five turnovers, isn’t worried because of all the new faces.

“It’s the second game of preseason with nine new players,’’ Randle said. “Nine is a lot. We got guys with the right attitude. I don’t know how long it will take. We’re not worried. We got to learn how to play with each other. We got to recognize team on a run and regroup and be more connected. We just scattered.”

The Knicks have a rigorous opening three games and not many exhibitions left to prepare. They will open in San Antonio on Oct. 23 before a back-to-back at Brooklyn then Boston in the home opener.

“Just clean up a few things,’’ said Barrett, who notched 15 points on 6-of-15 shooting. “It’s why you have preseason. It’s not that bad. We got to figure it out. One thing I’ll say, it’s fun to play with these guys. When the season gets started it’ll be more fun. I think we’ll do well. The Garden is legendary. We’re up for the challenge.”

It didn’t look that way Friday. Coach David Fizdale said the players “stopped guarding the 3.’’

”We weren’t getting that next step like we were in the first game,’’ said Fizdale, who gave his team Saturday off. “We watched the tape in our first game and saw the commitment to get to shooters.”

Fizdale still is figuring out his starting point guard. Front-runner Elfrid Payton started the first two games but suffered a setback Friday — 0-for-9 shooting with two turnovers and two assists. Fizdale said the offense was not “organized worth a crap.’’

Frank Ntilikina looked good in relief, posting three assists with solid defense, but fell into foul trouble.

The wild card is Dennis Smith Jr., who missed the first two games with a bad back but still is a starting candidate if he returns by Wednesday.

“I still want to see him, because he put in so much work this summer and I don’t think it’s fair for him to keep the same eyes from last year on him,’’ Fizdale said.

“We want to get a fresh set of eyes. He had a heck of a camp up to the point where he got sprained. I’d like to see him play two games before the preseason’s over.”

The Knicks were also missing Kevin Knox (calf strain), expected to be the backup small forward, especially with Marcus Morris’ offensive roll.

Dangerous from 3, Morris is averaging 19 points on 14-of-25 shooting. It prompted MSG Network’s Wally Sczcerbiak, to compare Morris to Carmelo Anthony.

That’s a bit much but MSG is already scratching for positives.

“We got punched in the mouth and didn’t recover,’’ Gibson said. “We get to beat each other up the next few days, lock in on defense, make our corrections and bounce back.”