Trail Blazers guard CJ Elleby collides with Knicks guard Evan...

Trail Blazers guard CJ Elleby collides with Knicks guard Evan Fournier during the first half of an NBA game in Portland, Ore., on Saturday. Credit: AP/Amanda Loman

PORTLAND, Ore. — The celebration was on. The Knicks were high-fiving as shot after shot dropped, and they could think about how they had survived the imposing five-game West Coast trip and the trade deadline and preserved a glimmer of hope.

But a 23-point lead over a Portland team shedding talent and eyeing the NBA Draft Lottery disappeared in a haze of missed shots, sore ankles and bad defense on Saturday. The Knicks were outscored 35-11 in the fourth quarter and lost to the Trail Blazers, 112-103, at Moda Center.

Afterward, they seemed confused about how this had happened. The Knicks (25-32), who ruined a chance to build off the impressive win at Golden State on Thursday, blew leads in three of their four losses on the trip. They also lost Mitchell Robinson and Cam Reddish, both of whom left the game with ankle soreness.

"We’ve just got to find a way to get that done," coach Tom Thibodeau said. "That’s what toughness is about. That’s why competitiveness, toughness, all that matters. Discipline. Sometimes it’s in your favor, sometimes it’s not. Everyone goes through long road trips. It’s part of it. But 35-11 in the fourth quarter, [allowing them to shoot] 48%, then badly outrebounded, it’s going to be hard to win that ballgame."

Julius Randle had 28 points, 16 rebounds and six assists. Kemba Walker added 23 points, hitting seven of his first eight shots before going cold, and Quentin Grimes added 20. But they got little from anyone else.

Robinson didn’t have a rebound in 14 minutes and scored just two points on a lob before exiting for the night.

"We were in the game and really gave ourselves a shot to win four of the five games," Randle said. "So I mean it’s encouraging in that sense. But it’s also very disappointing that we were 1-4, easily could have gone 4-1. It’s tough. It’s tough. But for me it [stinks], got a long plane ride back home. Flush it and see how I can help our team get to the [All-Star] break these last two games and finish off strong."

Anfernee Simons had 30 points and Josh Hart added 23 for the Trail Blazers (23-34), who took a 12-0 lead. That led to a 35-point swing in the Knicks’ direction followed by a 32-point swing in Portland’s direction.

Grimes had 14 points and Randle and Walker added 10 each as the Knicks outscored the Blazers 39-29 in the third quarter, but after bringing a 15-point lead into the fourth, they shot 3-for-18.

Up 82-59 in the third quarter, the Knicks just went ice cold. The Blazers went on a 40-16 run to take a 99-98 lead with 4:23 left. It was the second-largest blown lead for the Knicks in 25 years.

"I don’t know. I don’t know. I don’t know," Walker said when asked how this had happened. "I gotta go back and watch the film, but yeah. I don’t know. It just fell apart, like you said. They got momentum, never looked back."

Was it fatigue, a team just out of gas at the end of a 10-day, five-game road trip?

"It’s how you define the toughness," Thibodeau said. "The toughness is you’re on the road a long time; maybe there is some fatigue, but to still have the ability to do all the things that are necessary, even though you may not be feeling your best. But we’re counting on each other to get the job done.

"So it’s five guys tied together on offense and five guys tied together on defense. If one guy is choosing not to do — even if it’s not going his way — then it’s going to hurt the group. And so that’s why you have to keep going, no matter what. Just keep going.

"And then everyone has the responsibility of protecting the basket. So that’s the No. 1 thing in defensive transition: protect the basket first. So if we don’t protect the basket, then you’re giving them easy [shots]. You’ve got a big lead, so the only way they can make it up is if you give them easy baskets and you give them open threes."