Iowa Gov. Terry Branstad speaks during an interview Thursday in his office at the Iowa Statehouse in Des Moines. (Patrick Semansky/AP)

Iowa Gov. Terry Branstad (R) thinks Ted Cruz has faded in his state and may falter more after a “poor performance” in Thursday night’s final debate before the caucuses.

Branstad, the longest serving governor in U.S. history, said both Chris Christie and Marco Rubio did “really well” during the debate. But he clearly believes Donald Trump has an advantage going into the final days.

“Jeb Bush, I think, did better than expected,” he added during a Friday interview with C-SPAN’s “Newsmakers,” which will air on Sunday.

Branstad, who announced last week that he wants Cruz to lose his state’s kick-off contest over his opposition to the Renewable Fuel Standard, was in the audience and recalled how the Texas senator got booed when he clashed with the moderators. “It was a poor performance on his part,” Branstad said, twisting the knife. “Some of the other candidates came across a lot better. … Renewable energy is very important to our state. A lot of jobs are at stake. … His stand on that issue is definitely going to hurt him. We’ve seen in recent polls he was ahead, but now he’s dropped behind Trump.”

Branstad, who is officially neutral, forecasts record turnout on Monday night, citing the large crowds that Donald Trump draws to his events.

“Trump had 1,700 people in Ottumwa,” said Branstad, in an interview conducted by reporters from The Washington Post and Politico. “I didn’t know there were 1,700 Republicans in Ottumwa! That’s a huge turnout.”

Branstad thinks Iowa might not winnow the field as much as it has in the past.

“Historically we’ve said there’s three tickets out of Iowa, but this time on the Republican side we have such a big field that I think there might be four or five,” he said. “It’s an expectations game. It’s not just who wins, but who beats expectations?”

Branstad said he personally has not decided whom he will secretly cast a ballot for.

“Iowa voters a lot of time wait until the last minute,” he said.

Rubio, the Florida senator who has been third in polls of Iowa this week, might be peaking in Iowa at the right time, Branstad believes, but he’s not sure whether he has the field program to capitalize.

“He had a very strong showing in that debate,” Branstad said. “He’s got some momentum going into it. … My sense is he doesn’t have as strong an organization as some of the other candidates. But there seems to be a lot of interest and enthusiasm for his candidacy. … Certainly, he’s one to watch.”

Several veterans of Branstad’s 2014 reelection campaign are helping the New Jersey governor. Christie was the chairman of the Republican Governors Association that year, and Branstad noted that he actually hosted a fundraiser for him in New Jersey at a golf club owned by Trump.

“Christie had a really good debate performance,” Branstad said. “We’ll see what kind of effect that has because the debate is so close to the voting on Monday night.”

Branstad spoke admiringly of Trump, saying it was impressive he could draw an overflow crowd to Drake University for his event to compete with the Fox News debate.

“Conventional wisdom says [skipping the debate] wasn’t a smart thing to do,” Branstad said. “He’s done a lot of things that conventional wisdom would say weren’t smart, but he seems to be holding up as the leader.”

He said “it’s hard to judge” whether the people who come to see Trump speak will vote for him.

“They’re saying we could have a snowstorm come in Sunday night. … That could affect it,” he said. “But I think it’s going to be a record turnout.”

Trump has passionate supporters, but by all accounts he does not have as strong a get-out-the-vote operation as Cruz, his main rival, whom polls show is trailing but within striking distance.

Branstad predicted that “tens of thousands of independents” will decide to caucus in the Republican race. “But we may see a significant number come out and caucus for Sanders,” he added.

There is a swath of people who can decide which party’s event to participate in.

Branstad said he “would have never imagined” the billionaire first-time candidate’s unorthodox approach would actually work. He noted how unusual it was when Trump showed up at the state fair last summer with his helicopter to give kids rides.

“Skipping the debate is certainly not something I would have advised, but he put on his own show,” the governor added.

“It’s kind of an outsider’s year,” he continued. “Everybody thought it was going to be a coronation for Secretary [Hillary] Clinton. Now we see Bernie Sanders is really surging. That race is going to be very close.”

With regard to the other side, he said “a lot may hinge on” whom supporters of Martin O’Malley break for when they do not get to the necessary 15 percent threshold after the first ballot.

Asked at the end of the C-SPAN interview about why Jeb Bush never caught fire, Branstad replied: “He might surprise some people as to how well he does. … It just depends on who turns out. I’m not going to pre-judge what’s going to happen on Monday night, because I’ve been surprised before.”

But there was no love lost whenever Cruz came up. Branstad’s son, Eric, runs an ethanol lobby group that has been running attack ads against Cruz. One of the Texan’s most prominent supporters, Bob Vander Plaats, ran against Branstad in the 2010 GOP gubernatorial primary.

Cruz responded to the governor’s criticism of him last week by lumping him in with “crony capitalists” and “the Washington cartel.”

"It is no surprise that the establishment is in full panic mode," Cruz said on the campaign trail. "As conservatives unite behind our campaign, we are going to see the Washington cartel firing every shot they can, every cannon they can, because the Washington cartel lives on cronyism. It lives on making deals."

Branstad says he was amused by the critique.

“I have no connection to Washington, D.C., or the lobbyists in D.C.,” he said. “He obviously doesn’t know me.”