IOWA CITY — The entire complexion of Iowa’s basketball season changed in about 40 minutes Thursday night.

Completely. Totally.

The Hawkeyes walked into Carver-Hawkeye Arena with a big chunk of their fan base doubting them, wondering if they could come within a few dozen points of instate rival Iowa State. Some looked at the fact that 25th-ranked Cyclones were favored by just 4½ points and wondered if it might be a misprint. Maybe it was supposed to be 14½? Possibly 24½?

Some saw that Cyclones point guard Monte Morris said he wanted to beat the Hawkeyes “badly’’ and feared he would get his way.

Then the Hawkeyes walked in — strutted really — and proved everyone wrong. Fans. media. Oddsmakers. Everybody.

They played by far their best defense of the season, outhustled the Cyclones at every turn, got 23 points from a very determined Peter Jok and significant contributions from almost everyone else in rolling to a stunning 78-64 victory over Iowa State.

The Hawkeyes (5-5) really were in control almost the entire way, using an early 10-0 run to open a double-digit lead. It was 44-29 at halftime. Iowa State never got closer than seven points the rest of the way and every time it seemed on the verge of a run, Jok or Nicholas Baer or Isaiah Moss or someone made some sort of play to keep it from getting seriously close.

“It felt great but at the end of the day, I’m just more happy for the guys on the team because we believe in each other and nobody was really believing in us,’’ said Jok, who avoided being the first Iowa player ever to lose to the Cyclones three consecutive times.

“It means a lot just because I have a few friends on the (Iowa State) team …’’ he added. “It’s one step for us now for the rest of the season. We know how to play defense now against a great team.’’

Defense clearly was the major problem for this young team through the first nine games of the season. Last Saturday, it allowed 98 points in a loss to an Omaha team that was trampled by the Cyclones by 44 points just two days later.

Is it any wonder there were so few believers?

“We knew the people in our locker room were the only ones who believed we could win the game,’’ Moss said.

Moss, a redshirt freshman who seems to gain confidence with every minute, scored 14 points with nine of them coming in the last eight minutes when the Cyclones were trying hard to come back.

Baer contributed 10 points and 8 rebounds, including five free throws in the final minute-and-a-half. Cordell Pemsl netted 11 points. Jordan Bohannon only had eight points but that included a 3-pointer with 5:54 to go after Iowa State had closed to within 60-53.

Iowa coach Fran McCaffery called it maybe the biggest shot of the game.

McCaffery, by the way, wasn’t exactly giddy after his team finally played defense for an entire game and finally beat a team someone has heard of. But he certainly was pleased.

“I felt like we had the potential to be better than we were playing,’’ McCaffery said. “I sort of kept saying it … But this is a team that is ranked so it is a step. But you can’t ever be satisfied.’’

Iowa State coach Steve Prohm obviously was not satisfied after the Cyclones lost to the Hawkeyes for only the second time since 2008.

“It’s just disappointing,’’ he said. “We were bad tonight. Give credit to Iowa but we were bad.’’

He said he felt his team played OK defensively in the second half, but it shot just 35.7 percent from the field, 26.7 percent from 3-point range.

“We lost that game in the first half,’’ Prohm added. “We were bad in the first half in every facet of the game.’’

Matt Thomas led the Cyclones (6-3) with 14 points and four other players had 10. Morris, who was mostly neutralized by Bohannon, added five rebounds and five assists although his biggest assist may have been to the Hawkeyes with his “beat them badly’’ comments.

“It definitely added a little motivation,’’ Bohannon said.

In the final minutes, the Iowa student section began the chant that even they probably never expected to be able to use in this game: “Hawkeye state, Hawkeye state.’’

The players heard it and responded a few minutes later by rushing over to celebrate with the students.

“It would been hard to miss it,’’ Baer said of the chant. “Being a kid from Bettendorf, our neighbor has a Cyclone in their yard and of course, we have a Hawkeye. It’s just kind of the way it is in our neighborhood. Half the people went to Iowa State and half went to Iowa. Things like that make this even more special.’’