GOP Senate candidate Mike Gibbons says his bus tour to nearly 90 Ohio counties could help him wrangle undecided primary voters after former President Donald Trump threw a "curveball" in the race by backing opponent J.D. Vance 

"We had a lot of people that came up and said we voted for you, we're going to for you," Gibbons told Fox News Sunday outside the Ottawa County Republican Women’s Club Chicken BBQ in Port Clinton. 

"It's what we felt all over the state," he added. "We have a lot of support and this election's not over." 

Ohio GOP Senate candidate Mike Gibbons speaks with Fox News Digital outside on Ottowa County Republican Women's Club event in Port Clinton, Ohio. (Tyler Olson/Fox News)

Ohio GOP Senate candidate Mike Gibbons speaks with Fox News Digital outside on Ottowa County Republican Women's Club event in Port Clinton, Ohio. (Tyler Olson/Fox News)

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Gibbons pulled up to the event in his trademark campaign bus and along with former Ohio GOP Chair Jane Timken and state Sen. Matt Dolan – also candidates in the GOP Senate primary – mingled with voters over lunch. 

Gibbons manned the lemonade station, lining up a row of cups for attendees as they came through the lunch line at a local Knights of Columbus club. 

The candidate said the support he saw in Port Clinton matched what he sees in many other far-flung areas of Ohio on his bus tour. 

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"I actually can't think of an area where we're weak," Gibbons said. "We've been everywhere in the state, 88 counties, in many counties we were the only ones that spent any time with them… I'm hopeful it will pay off. We're gonna see how smart the voters of Ohio are here in a few days." 

Ohio GOP Senate candidate Mike Gibbons steps out of his campaign bus before an Ottawa County Republican Women's Club event in Port Clinton, Ohio. (Tyler Olson/Fox News)

Ohio GOP Senate candidate Mike Gibbons steps out of his campaign bus before an Ottawa County Republican Women's Club event in Port Clinton, Ohio. (Tyler Olson/Fox News)

The event came down the final stretch of a campaign that's been dominated by four of the top candidates, including Gibbons, fighting hard for Trump's endorsement. Gibbons, an investment banker by trade, appeared to be a potential option, particularly given his comparison to Trump as a businessman who decided to run for office. 

But Vance, a former businessman himself and the author of "Hillbilly Elegy," eventually got Trump's support. This was despite many comments Vance made in 2016 that were highly critical of Trump and his voters.

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Gibbons called the move by Trump a mistake. 

"I'm a pro-America First candidate. I supported Donald Trump… I don't think he made a good decision coming into this race, particularly this late in the game," Gibbons said Sunday. "He took a guy that was single digits and made him competitive…. and I think a lot of Republicans in the state, conservatives in this state are concerned about that. They don't want to be told who to vote for by some guy from the West coast… People are upset." 

Trump gave critics of his endorsement of Vance even more ammunition at a Sunday night rally in Nebraska. The former president stumbled over his words, saying that he endorsed "J.P., right? J.D. Mandel," in the Ohio race. 

Ohio GOP Senate candidate Mike Gibbons serves lemonade to voters at an Ottawa County Republican Women's Club event in Port Clinton, Ohio. (Tyler Olson/Fox News)

Ohio GOP Senate candidate Mike Gibbons serves lemonade to voters at an Ottawa County Republican Women's Club event in Port Clinton, Ohio. (Tyler Olson/Fox News)

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Gibbons' campaign immediately attacked Vance over the moment. "Vance's momentum, just like his MAGA credentials, are fake," it said in a press release. 

Vance regularly acknowledges his previous comments about Trump in campaign stops. He tells voters that he's had an earnest change of mind about Trump, and touts endorsements from MAGA-world regulars like Reps. Marjorie Taylor Greene, R-Ga., and Matt Gaetz, R-Fla., as proof he's now pro-Trump.

"I just think you have to tell the truth. Right? A lot of people changed their mind on Donald Trump, and I'm one of them," Vance said Saturday. "It's not really about what I said about Trump six years ago."

Despite the "curveball," Gibbons said, he believed the Trump endorsement changed the minds of very few of his supporters. 

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Voters will go to the polls in the high-profile, expensive and contentious Senate primary on Tuesday, with Vance, Gibbons, Dolan and former state Treasurer Josh Mandel all seemingly within striking distance in many polls. And with a massive number of undecideds, Timken also maintains that she can pull out a late win thanks to her sprawling ground game. 

The winner of the GOP primary will likely face Rep. Tim Ryan, D-Ohio, in the general election in November.