By JOHN BOHNENKAMP

IOWA CITY, Iowa — Ben McCollum and his players knew an opportunity was missed.

The setup was perfect on Saturday at Carver-Hawkeye Arena — a sellout crowd for the first time this season, a nationally-ranked opponent in town for a nationally-televised game, a chance for a signature win in the first season of McCollum as Iowa’s head men’s basketball coach.

Then the Hawkeyes went out and lost to No. 13 Purdue 78-57.

“I don’t think we were ready to play today,” senior guard Bennett Stirtz said. “It definitely showed, and we’re sorry. Sorry to our fans who had to show up for that and had to watch that.”

Rebuilding a program wasn’t going to be easy, McCollum said, but part of that rebuild had to be luring the fans back to Carver-Hawkeye.

Saturday’s crowd was officially listed at 14,998 — granted, some of them were boisterous Purdue fans who were able to snag some tickets — and the Hawkeyes were hoping to show what they have built this season.

Instead they showed the pains that come with a new coach and a roster that is almost entirely different from last season.

“The crowd was awesome,” McCollum said. “We felt like we’re connected with the community. It was awesome that they showed up. Disappointed in just us. Just weren’t great.”

Iowa (18-7 overall, 8-6 Big Ten) had won six of their last seven games. That one loss was Wednesday’s 77-70 defeat at Maryland, and if there was residue from that performance, McCollum didn’t feel it.

“I thought we were really prepared,” McCollum said. “We had a great practice the day before.”

What McCollum thought was the problem in this game was Iowa’s offense, which was unsteady until the game got out of hand, and then suddenly the Hawkeyes started making shots. They shot 37.7% for the game, but making nine of their final 13 shots skewed that number.

“For some reason, we’re not scoring,” McCollum said. “We’re just not clicking on offense. The ball is not moving. We get in the paint and we should pass and we try to shoot it. And as you take a contested-at-the-rim shot and you miss it, that’s a turnover. Layups that you miss are turnovers, and then they get out in transition, and then we couldn’t set our defense, and then you’ve got problems.”

“They were pretty big, so it’s hard to get some shots off, but I think we should be better about making reads,” forward Cam Manyawu said. “When they’ve got two on the ball, we have to pass it out and have better reads. I think that’s kind of our biggest thing that we have to get better at when it comes to playing against size and just taking better shots.”

Purdue (21-4, 11-3) changed its defensive approach against the Hawkeyes, coach Matt Painter said. In the Boilermakers’ 79-72 win over Iowa on January 14, the defensive focus was so much on Stirtz, it allowed Kael Combs, Tate Sage and Tavion Banks to combine for nine 3-pointers.

“Tonight, they had zero,” Painter said. “I thought, from our standpoint, we didn’t overdo him.”

Stirtz finished with 19 points, but no other Hawkeye was in double figures.

“I thought they still paid attention to him a good amount,” McCollum said. “I thought they’ve gotten better defensively since the first time we played them.”

Purdue efficiently carved Iowa’s defense. The Boilermakers, who lead the nation in assists per game, had 20 assists on 25 field goals, with Braden Smith leading the way with 12 assists.

The Boilermakers shot 47.2% for the game, but had a first-half run of 15-2 and a second-half run of 22-6. C.J. Cox and Gicarri Harris had 14 points each to lead Purdue, while Trey Kaufman-Renn had 12 points and 12 rebounds and Fletcher Loyer added 12 points.

McCollum knew what had been squandered on this day.

“Maybe they were tense, maybe they wanted to win and they were too geeked up,” he said. “Maybe I missed that, but I’m not embarrassed, and I’m proud of my team. I’m not proud of our performance tonight whatsoever. I am ready to fight, and we’re gonna fight, and that’s what we do.”

Photo: Iowa’s Tavion Banks fights for a loose ball in Saturday’s game against Purdue. (Keith Gillett/Icon Sportswire)